Exercise 1 Page 45

Think of the point where the graph of an equation crosses the x-axis. The y-value of that ( x, y) coordinate pair is 0, and the x-value is the x-intercept. To find the x-intercept of the equation, we should substitute 0 for y and solve for x.

y=2x+7

Substitute

y= 0

0=2x+7

SubEqn

LHS-7=RHS-7

-7=2x

DivEqn

.LHS /2.=.RHS /2.

-7/2=x

RearrangeEqn

Rearrange equation

x=-7/2

An x-intercept of - 72 means that the graph passes through the x-axis at the point ( - 72,0).