Precalculus Examples

y = - 2 X

$y = - 2 X$

Step 1

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

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Step 1.1

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 1.2

Find the values of

m

$m$ and

b

$b$ using the form

y = m x + b

$y = m x + b$ .

m = - 2

$m = - 2$

b = 0

$b = 0$

Step 1.3

The slope of the line is the value of

m

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

b

$b$ .

Slope:

- 2

$- 2$

y-intercept:

(0, 0)

$(0, 0)$

Slope:

- 2

$- 2$

y-intercept:

(0, 0)

$(0, 0)$

Step 2

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 2.1

Create a table of the

x

$x$ and

y

$y$ values.

\begin{matrix} x & y 0 & 0 1 & - 2 \end{matrix}

$\begin{array}{c} x & y \\ 0 & 0 \\ 1 & - 2 \end{array}$

\begin{matrix} x & y 0 & 0 1 & - 2 \end{matrix}

$\begin{array}{c} x & y \\ 0 & 0 \\ 1 & - 2 \end{array}$

Step 3

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

Slope:

- 2

$- 2$

y-intercept:

(0, 0)

$(0, 0)$

\begin{matrix} x & y 0 & 0 1 & - 2 \end{matrix}

$\begin{array}{c} x & y \\ 0 & 0 \\ 1 & - 2 \end{array}$

Step 4