Exercise 7 Page 177

To determine the x-intercept for the given equation, we will substitute 0 for y and solve for x. To determine the y-intercept, we will substitute 0 for x and solve for y.

Finding the x-intercept

Think of the point where the graph of an equation crosses the x-axis. The y-value of that (x,y) coordinate pair is equal to 0, and the x-value is the x-intercept. Consider the given equation. 3/5x+1/2y=30Let's substitute 0 for y and solve for x.

3/5x+1/2y=30

Substitute

y= 0

3/5x+1/2( 0)=30

ZeroPropMult

Zero Property of Multiplication

3/5x=30

MultEqn

LHS * 5=RHS* 5

3x=150

DivEqn

.LHS /3.=.RHS /3.

x=50

The x-intercept of the equation is 50.

Finding the y-intercept

In the same way as above, now consider the point where the graph of the equation crosses the y-axis. The x-value of the (x,y) coordinate pair at the y-intercept is 0. Therefore, substituting 0 for x will give us the y-intercept.

3/5x+1/2y=30

Substitute

x= 0

3/5( 0)+1/2y=30

ZeroPropMult

Zero Property of Multiplication

1/2y=30

MultEqn

LHS * 2=RHS* 2

y=60

The y-intercept of the equation is 60.