Pre-Algebra Examples

x + y = 7

$x + y = 7$

Step 1

Subtract

x

$x$ from both sides of the equation.

y = 7 - x

$y = 7 - x$

Step 2

Rewrite in slope-intercept form.

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Step 2.1

The slope-intercept form is

y = m x + b

$y = m x + b$ , where

m

$m$ is the slope and

b

$b$ is the y-intercept.

y = m x + b

$y = m x + b$

Step 2.2

Reorder

7

$7$ and

- x

$- x$ .

y = - x + 7

$y = - x + 7$

y = - x + 7

$y = - x + 7$

Step 3

Use the slope-intercept form to find the slope and y-intercept.

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Step 3.1

Find the values of

m

$m$ and

b

$b$ using the form

y = m x + b

$y = m x + b$ .

m = - 1

$m = - 1$

b = 7

$b = 7$

Step 3.2

The slope of the line is the value of

m

$m$ , and the y-intercept is the value of

b

$b$ .

Slope:

- 1

$- 1$

y-intercept:

(0, 7)

$(0, 7)$

Slope:

- 1

$- 1$

y-intercept:

(0, 7)

$(0, 7)$

Step 4

Any line can be graphed using two points. Select two

x

$x$ values, and plug them into the equation to find the corresponding

y

$y$ values.

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Step 4.1

Reorder

7

$7$ and

- x

$- x$ .

y = - x + 7

$y = - x + 7$

Step 4.2

Create a table of the

x

$x$ and

y

$y$ values.

\begin{array}{c} x & y \\ 0 & 7 \\ 1 & 6 \end{array}

$\begin{array}{c} x & y \\ 0 & 7 \\ 1 & 6 \end{array}$

\begin{array}{c} x & y \\ 0 & 7 \\ 1 & 6 \end{array}

$\begin{array}{c} x & y \\ 0 & 7 \\ 1 & 6 \end{array}$

Step 5

Graph the line using the slope and the y-intercept, or the points.

Slope:

- 1

$- 1$

y-intercept:

(0, 7)

$(0, 7)$

\begin{array}{c} x & y \\ 0 & 7 \\ 1 & 6 \end{array}

$\begin{array}{c} x & y \\ 0 & 7 \\ 1 & 6 \end{array}$

Step 6