Algebra Examples

$x^{2} + y^{2} + 8 x - 8 y - 49 = 0$

Step 1

Find the x-intercepts.

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Step 1.1

To find the x-intercept(s), substitute in $0$ for $y$ and solve for $x$ .

$x^{2} + {(0)}^{2} + 8 x - 8 \cdot 0 - 49 = 0$

Step 1.2

Solve the equation.

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Step 1.2.1

Simplify $x^{2} + {(0)}^{2} + 8 x - 8 \cdot 0 - 49$ .

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Step 1.2.1.1

Simplify each term.

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Step 1.2.1.1.1

Raising $0$ to any positive power yields $0$ .

$x^{2} + 0 + 8 x - 8 \cdot 0 - 49 = 0$

Step 1.2.1.1.2

Multiply $- 8$ by $0$ .

$x^{2} + 0 + 8 x + 0 - 49 = 0$

Step 1.2.1.2

Combine the opposite terms in $x^{2} + 0 + 8 x + 0 - 49$ .

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Step 1.2.1.2.1

Add $x^{2}$ and $0$ .

$x^{2} + 8 x + 0 - 49 = 0$

Step 1.2.1.2.2

Add $x^{2} + 8 x$ and $0$ .

$x^{2} + 8 x - 49 = 0$

Step 1.2.2

Use the quadratic formula to find the solutions.

$\frac{- b \pm \sqrt{b^{2} - 4 (a c)}}{2 a}$

Step 1.2.3

Substitute the values $a = 1$ , $b = 8$ , and $c = - 49$ into the quadratic formula and solve for $x$ .

$\frac{- 8 \pm \sqrt{8^{2} - 4 \cdot (1 \cdot - 49)}}{2 \cdot 1}$

Step 1.2.4

Simplify.

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Step 1.2.4.1

Simplify the numerator.

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Step 1.2.4.1.1

Raise $8$ to the power of $2$ .

$x = \frac{- 8 \pm \sqrt{64 - 4 \cdot 1 \cdot - 49}}{2 \cdot 1}$

Step 1.2.4.1.2

Multiply $- 4 \cdot 1 \cdot - 49$ .

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Step 1.2.4.1.2.1

Multiply $- 4$ by $1$ .

$x = \frac{- 8 \pm \sqrt{64 - 4 \cdot - 49}}{2 \cdot 1}$

Step 1.2.4.1.2.2

Multiply $- 4$ by $- 49$ .

$x = \frac{- 8 \pm \sqrt{64 + 196}}{2 \cdot 1}$

Step 1.2.4.1.3

Add $64$ and $196$ .

$x = \frac{- 8 \pm \sqrt{260}}{2 \cdot 1}$

Step 1.2.4.1.4

Rewrite $260$ as $2^{2} \cdot 65$ .

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Step 1.2.4.1.4.1

Factor $4$ out of $260$ .

$x = \frac{- 8 \pm \sqrt{4 (65)}}{2 \cdot 1}$

Step 1.2.4.1.4.2

Rewrite $4$ as $2^{2}$ .

$x = \frac{- 8 \pm \sqrt{2^{2} \cdot 65}}{2 \cdot 1}$

Step 1.2.4.1.5

Pull terms out from under the radical.

$x = \frac{- 8 \pm 2 \sqrt{65}}{2 \cdot 1}$

Step 1.2.4.2

Multiply $2$ by $1$ .

$x = \frac{- 8 \pm 2 \sqrt{65}}{2}$

Step 1.2.4.3

Simplify $\frac{- 8 \pm 2 \sqrt{65}}{2}$ .

$x = - 4 \pm \sqrt{65}$

Step 1.2.5

Simplify the expression to solve for the $+$ portion of the $\pm$ .

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Step 1.2.5.1

Simplify the numerator.

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Step 1.2.5.1.1

Raise $8$ to the power of $2$ .

$x = \frac{- 8 \pm \sqrt{64 - 4 \cdot 1 \cdot - 49}}{2 \cdot 1}$

Step 1.2.5.1.2

Multiply $- 4 \cdot 1 \cdot - 49$ .

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Step 1.2.5.1.2.1

Multiply $- 4$ by $1$ .

$x = \frac{- 8 \pm \sqrt{64 - 4 \cdot - 49}}{2 \cdot 1}$

Step 1.2.5.1.2.2

Multiply $- 4$ by $- 49$ .

$x = \frac{- 8 \pm \sqrt{64 + 196}}{2 \cdot 1}$

Step 1.2.5.1.3

Add $64$ and $196$ .

$x = \frac{- 8 \pm \sqrt{260}}{2 \cdot 1}$

Step 1.2.5.1.4

Rewrite $260$ as $2^{2} \cdot 65$ .

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Step 1.2.5.1.4.1

Factor $4$ out of $260$ .

$x = \frac{- 8 \pm \sqrt{4 (65)}}{2 \cdot 1}$

Step 1.2.5.1.4.2

Rewrite $4$ as $2^{2}$ .

$x = \frac{- 8 \pm \sqrt{2^{2} \cdot 65}}{2 \cdot 1}$

Step 1.2.5.1.5

Pull terms out from under the radical.

$x = \frac{- 8 \pm 2 \sqrt{65}}{2 \cdot 1}$

Step 1.2.5.2

Multiply $2$ by $1$ .

$x = \frac{- 8 \pm 2 \sqrt{65}}{2}$

Step 1.2.5.3

Simplify $\frac{- 8 \pm 2 \sqrt{65}}{2}$ .

$x = - 4 \pm \sqrt{65}$

Step 1.2.5.4

Change the $\pm$ to $+$ .

$x = - 4 + \sqrt{65}$

Step 1.2.6

Simplify the expression to solve for the $-$ portion of the $\pm$ .

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Step 1.2.6.1

Simplify the numerator.

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Step 1.2.6.1.1

Raise $8$ to the power of $2$ .

$x = \frac{- 8 \pm \sqrt{64 - 4 \cdot 1 \cdot - 49}}{2 \cdot 1}$

Step 1.2.6.1.2

Multiply $- 4 \cdot 1 \cdot - 49$ .

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Step 1.2.6.1.2.1

Multiply $- 4$ by $1$ .

$x = \frac{- 8 \pm \sqrt{64 - 4 \cdot - 49}}{2 \cdot 1}$

Step 1.2.6.1.2.2

Multiply $- 4$ by $- 49$ .

$x = \frac{- 8 \pm \sqrt{64 + 196}}{2 \cdot 1}$

Step 1.2.6.1.3

Add $64$ and $196$ .

$x = \frac{- 8 \pm \sqrt{260}}{2 \cdot 1}$

Step 1.2.6.1.4

Rewrite $260$ as $2^{2} \cdot 65$ .

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Step 1.2.6.1.4.1

Factor $4$ out of $260$ .

$x = \frac{- 8 \pm \sqrt{4 (65)}}{2 \cdot 1}$

Step 1.2.6.1.4.2

Rewrite $4$ as $2^{2}$ .

$x = \frac{- 8 \pm \sqrt{2^{2} \cdot 65}}{2 \cdot 1}$

Step 1.2.6.1.5

Pull terms out from under the radical.

$x = \frac{- 8 \pm 2 \sqrt{65}}{2 \cdot 1}$

Step 1.2.6.2

Multiply $2$ by $1$ .

$x = \frac{- 8 \pm 2 \sqrt{65}}{2}$

Step 1.2.6.3

Simplify $\frac{- 8 \pm 2 \sqrt{65}}{2}$ .

$x = - 4 \pm \sqrt{65}$

Step 1.2.6.4

Change the $\pm$ to $-$ .

$x = - 4 - \sqrt{65}$

Step 1.2.7

The final answer is the combination of both solutions.

$x = - 4 + \sqrt{65}, - 4 - \sqrt{65}$

Step 1.3

x-intercept(s) in point form.

x-intercept(s): $(- 4 + \sqrt{65}, 0), (- 4 - \sqrt{65}, 0)$

Step 2

Find the y-intercepts.

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Step 2.1

To find the y-intercept(s), substitute in $0$ for $x$ and solve for $y$ .

${(0)}^{2} + y^{2} + 8 (0) - 8 y - 49 = 0$

Step 2.2

Solve the equation.

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Step 2.2.1

Simplify ${(0)}^{2} + y^{2} + 8 (0) - 8 y - 49$ .

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Step 2.2.1.1

Simplify each term.

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Step 2.2.1.1.1

Raising $0$ to any positive power yields $0$ .

$0 + y^{2} + 8 (0) - 8 y - 49 = 0$

Step 2.2.1.1.2

Multiply $8$ by $0$ .

$0 + y^{2} + 0 - 8 y - 49 = 0$

Step 2.2.1.2

Combine the opposite terms in $0 + y^{2} + 0 - 8 y - 49$ .

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Step 2.2.1.2.1

Add $0$ and $y^{2}$ .

$y^{2} + 0 - 8 y - 49 = 0$

Step 2.2.1.2.2

Add $y^{2}$ and $0$ .

$y^{2} - 8 y - 49 = 0$

Step 2.2.2

Use the quadratic formula to find the solutions.

$\frac{- b \pm \sqrt{b^{2} - 4 (a c)}}{2 a}$

Step 2.2.3

Substitute the values $a = 1$ , $b = - 8$ , and $c = - 49$ into the quadratic formula and solve for $y$ .

$\frac{8 \pm \sqrt{{(- 8)}^{2} - 4 \cdot (1 \cdot - 49)}}{2 \cdot 1}$

Step 2.2.4

Simplify.

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Step 2.2.4.1

Simplify the numerator.

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Step 2.2.4.1.1

Raise $- 8$ to the power of $2$ .

$y = \frac{8 \pm \sqrt{64 - 4 \cdot 1 \cdot - 49}}{2 \cdot 1}$

Step 2.2.4.1.2

Multiply $- 4 \cdot 1 \cdot - 49$ .

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Step 2.2.4.1.2.1

Multiply $- 4$ by $1$ .

$y = \frac{8 \pm \sqrt{64 - 4 \cdot - 49}}{2 \cdot 1}$

Step 2.2.4.1.2.2

Multiply $- 4$ by $- 49$ .

$y = \frac{8 \pm \sqrt{64 + 196}}{2 \cdot 1}$

Step 2.2.4.1.3

Add $64$ and $196$ .

$y = \frac{8 \pm \sqrt{260}}{2 \cdot 1}$

Step 2.2.4.1.4

Rewrite $260$ as $2^{2} \cdot 65$ .

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Step 2.2.4.1.4.1

Factor $4$ out of $260$ .

$y = \frac{8 \pm \sqrt{4 (65)}}{2 \cdot 1}$

Step 2.2.4.1.4.2

Rewrite $4$ as $2^{2}$ .

$y = \frac{8 \pm \sqrt{2^{2} \cdot 65}}{2 \cdot 1}$

Step 2.2.4.1.5

Pull terms out from under the radical.

$y = \frac{8 \pm 2 \sqrt{65}}{2 \cdot 1}$

Step 2.2.4.2

Multiply $2$ by $1$ .

$y = \frac{8 \pm 2 \sqrt{65}}{2}$

Step 2.2.4.3

Simplify $\frac{8 \pm 2 \sqrt{65}}{2}$ .

$y = 4 \pm \sqrt{65}$

Step 2.2.5

Simplify the expression to solve for the $+$ portion of the $\pm$ .

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Step 2.2.5.1

Simplify the numerator.

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Step 2.2.5.1.1

Raise $- 8$ to the power of $2$ .

$y = \frac{8 \pm \sqrt{64 - 4 \cdot 1 \cdot - 49}}{2 \cdot 1}$

Step 2.2.5.1.2

Multiply $- 4 \cdot 1 \cdot - 49$ .

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Step 2.2.5.1.2.1

Multiply $- 4$ by $1$ .

$y = \frac{8 \pm \sqrt{64 - 4 \cdot - 49}}{2 \cdot 1}$

Step 2.2.5.1.2.2

Multiply $- 4$ by $- 49$ .

$y = \frac{8 \pm \sqrt{64 + 196}}{2 \cdot 1}$

Step 2.2.5.1.3

Add $64$ and $196$ .

$y = \frac{8 \pm \sqrt{260}}{2 \cdot 1}$

Step 2.2.5.1.4

Rewrite $260$ as $2^{2} \cdot 65$ .

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Step 2.2.5.1.4.1

Factor $4$ out of $260$ .

$y = \frac{8 \pm \sqrt{4 (65)}}{2 \cdot 1}$

Step 2.2.5.1.4.2

Rewrite $4$ as $2^{2}$ .

$y = \frac{8 \pm \sqrt{2^{2} \cdot 65}}{2 \cdot 1}$

Step 2.2.5.1.5

Pull terms out from under the radical.

$y = \frac{8 \pm 2 \sqrt{65}}{2 \cdot 1}$

Step 2.2.5.2

Multiply $2$ by $1$ .

$y = \frac{8 \pm 2 \sqrt{65}}{2}$

Step 2.2.5.3

Simplify $\frac{8 \pm 2 \sqrt{65}}{2}$ .

$y = 4 \pm \sqrt{65}$

Step 2.2.5.4

Change the $\pm$ to $+$ .

$y = 4 + \sqrt{65}$

Step 2.2.6

Simplify the expression to solve for the $-$ portion of the $\pm$ .

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Step 2.2.6.1

Simplify the numerator.

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Step 2.2.6.1.1

Raise $- 8$ to the power of $2$ .

$y = \frac{8 \pm \sqrt{64 - 4 \cdot 1 \cdot - 49}}{2 \cdot 1}$

Step 2.2.6.1.2

Multiply $- 4 \cdot 1 \cdot - 49$ .

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Step 2.2.6.1.2.1

Multiply $- 4$ by $1$ .

$y = \frac{8 \pm \sqrt{64 - 4 \cdot - 49}}{2 \cdot 1}$

Step 2.2.6.1.2.2

Multiply $- 4$ by $- 49$ .

$y = \frac{8 \pm \sqrt{64 + 196}}{2 \cdot 1}$

Step 2.2.6.1.3

Add $64$ and $196$ .

$y = \frac{8 \pm \sqrt{260}}{2 \cdot 1}$

Step 2.2.6.1.4

Rewrite $260$ as $2^{2} \cdot 65$ .

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Step 2.2.6.1.4.1

Factor $4$ out of $260$ .

$y = \frac{8 \pm \sqrt{4 (65)}}{2 \cdot 1}$

Step 2.2.6.1.4.2

Rewrite $4$ as $2^{2}$ .

$y = \frac{8 \pm \sqrt{2^{2} \cdot 65}}{2 \cdot 1}$

Step 2.2.6.1.5

Pull terms out from under the radical.

$y = \frac{8 \pm 2 \sqrt{65}}{2 \cdot 1}$

Step 2.2.6.2

Multiply $2$ by $1$ .

$y = \frac{8 \pm 2 \sqrt{65}}{2}$

Step 2.2.6.3

Simplify $\frac{8 \pm 2 \sqrt{65}}{2}$ .

$y = 4 \pm \sqrt{65}$

Step 2.2.6.4

Change the $\pm$ to $-$ .

$y = 4 - \sqrt{65}$

Step 2.2.7

The final answer is the combination of both solutions.

$y = 4 + \sqrt{65}, 4 - \sqrt{65}$

Step 2.3

y-intercept(s) in point form.

y-intercept(s): $(0, 4 + \sqrt{65}), (0, 4 - \sqrt{65})$

Step 3

List the intersections.

x-intercept(s): $(- 4 + \sqrt{65}, 0), (- 4 - \sqrt{65}, 0)$

y-intercept(s): $(0, 4 + \sqrt{65}), (0, 4 - \sqrt{65})$

Step 4