Exercise 7 Page 495

Equations in slope-intercept form follow a certain format. y=mx+ b In this format m is the slope and b is the y-intercept. The line has a slope of 12 which means that we can substitute m=12. y=1/2x+ b To write a complete equation for this line, we also need to determine the y-intercept b. We can do that by substituting the given point (2,- 4) into the equation and solving for b.

y=1/2x+b

SubstituteII

x= 2, y= - 4

- 4=1/2( 2)+b

▼

Solve for b

MoveRightFacToNumOne

1/b* a = a/b

- 4=2/2+b

QuotOne

a/a=1

- 4=1+b

SubEqn

LHS-1=RHS-1

- 5=b

RearrangeEqn

Rearrange equation

b= - 5

Now that we have both the slope and the y-intercept, we can write the final equation. y=1/2x+( - 5) ⇔ y=1/2x - 5