Page 105 - Math Course 3 (Book 1)

The Slope-Intercept Form

Real World Example Your Turn!

BAKING
A school group making cookies for a bake sale Graph an Equation
spends $75 on ingredients and then sells the
cookies for $5 a dozen. The amount earned y can Graph –2x + 3y = 12 using the slope and y-intercept.
be represented by the equation y = 5x – 75, where x
equals the number of dozens sold.
A. B.
Graph the equation.

First, find the slope and the y-intercept.
slope = 5
y-intercept = –75

Plot the point at (0, –75). Then go up 5 and right 1.
Connect these points. C. D.

150
Amount Earned ($) –50 10 20 30 40 50 Answer
100
50
0

–100

Number of Dozens Sold

The y-intercept –75 represents
the cost of the ingredients. Slope
Answer
5 represents the dollars earned
per dozen cookies.

Real World Example

T-SHIRTS
A T-shirt company spends $150 on materials to make T-shirts and then sells the shirts for $12 each. The
amount earned y can be represented by the equation y = 12x – 150, where x represents the number of shirts
sold. Graph the equation.

A. B. Answer
Amount Earned ($) Amount Earned ($)

T-shirt Sold T-shirt Sold
C. D.
Amount Earned ($) Amount Earned ($)

T-shirt Sold T-shirt Sold
97