Pre-Algebra Examples

$p (x) = 85 - 3 x$

Step 1

Rewrite the function as an equation.

$y = 85 - 3 x$

Step 2

Reorder $85$ and $- 3 x$ .

$y = - 3 x + 85$

Step 3

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

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Step 3.1

The slope-intercept form is $y = m x + b$ , where $m$ is the slope and $b$ is the y-intercept.

$y = m x + b$

Step 3.2

Find the values of $m$ and $b$ using the form $y = m x + b$ .

$m = - 3$

$b = 85$

Step 3.3

The slope of the line is the value of $m$ , and the y-intercept is the value of $b$ .

Slope: $- 3$

y-intercept: $(0, 85)$

Slope: $- 3$

y-intercept: $(0, 85)$

Step 4

Any line can be graphed using two points. Select two $x$ values, and plug them into the equation to find the corresponding $y$ values.

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Step 4.1

Reorder $85$ and $- 3 x$ .

$y = - 3 x + 85$

Step 4.2

Create a table of the $x$ and $y$ values.

$\begin{array}{c} x & y \\ 0 & 85 \\ 1 & 82 \end{array}$

Step 5

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

Slope: $- 3$

y-intercept: $(0, 85)$

$\begin{array}{c} x & y \\ 0 & 85 \\ 1 & 82 \end{array}$

Step 6