Exercise 2 Page 242

What do parallel lines have in common?

y=-4x+4

Practice makes perfect

Consider the given equation of a line. y= -4x+5 When lines are parallel, they have the same slope. Because of this, we know that all lines that are parallel to the line whose equation is given will have a slope of -4. We can write a general equation in slope-intercept form for these lines. y= -4x+ b We are asked to write the equation of a line parallel to the given equation that passes through the point ( 0, 4). By substituting this point into the above equation for x and y, we will be able to solve for the y-intercept b of the parallel line.

y=-4x+b

SubstituteII

x= 0, y= 4

4=-4( 0)+b

ZeroPropMult

Zero Property of Multiplication

4=0+b

AddTerms

Add terms

4=b

RearrangeEqn

Rearrange equation