1. Do-Now Evaluate the expression when x = –3. –5 ANSWER 1. 3x + 4 12
–15
4. The amount a that a taxi service charges is given by
a = 1.5m where m is the number of miles. Find a when m is 7.
ANSWER
$10.50

2. Find the intercepts of the graph of an equation
Lesson 4.3
Find the intercepts of the graph of an equation
Find the x-intercept and the y-intercept of the graph of 2x + 7y = 28.
SOLUTION
To find the x-intercept, substitute 0 for y and solve for x.
2x + 7y = 28
Write original equation.
2x + 7(0) = 28
Substitute 0 for y.
x =
= 14 28 2
Solve for x.
To find the y-intercept, substitute 0 for x and solve for y.
ANSWER
The x-intercept is 14. The y-intercept is 4.

3. GUIDED PRACTICE 1. 3x + 2y = 6 2. 4x – 2y = 10 3. – 3x + 5y = – 15
Find the x-intercept and the y-intercept of the graph of the equations.
x + 2y = 6
x – 2y = 10
3. – 3x + 5y = – 15

4. Use intercepts to graph an equation
EXAMPLE
Use intercepts to graph an equation
Graph the equation x + 2y = 4.
SOLUTION
STEP 1
Find the intercepts.
x + 2y = 4
x + 2y = 4
x + 2(0) = 4
0 + 2y = 4
x = 
x-intercept 4
y = 
y-intercept 2
STEP 2
Plot points. The x-intercept is 4, so plot the point (4, 0). The y- intercept is 2, so plot the point (0, 2). Draw a line through the points.