Exercise 4 Page 193

Slope-intercept form is a form of equation where m represents the slope of the line and b represents the y-intercept. y=mx+ b To write an equation for a line in this form, we must find the slope and the y-intercept. We will begin by finding the slope of the line that connects the given points, ( 3, 3) and ( 4, 7), using the Slope Formula.

m=y_2-y_1/x_2-x_1

SubstitutePoints

Substitute ( 3,3) & ( 4,7)

m=7 - 3/4- 3

SubTerms

Subtract terms

m=4/1

DivByOne

a/1=a

m=4

The slope of the line is 4. This means that for every 1 unit we move to the right on a coordinate plane, we move 4 units up. At this point, we have the following equation. y = 4x + b To determine the value of b we can substitute either of the given points into the equation for x and y, then solve. We will use ( 3, 3).

y=4x+b

SubstituteII

x= 3, y= 3

3 = 4( 3) + b

▼

Solve for b

Multiply

3=12+b

SubEqn

LHS-12=RHS-12

-9=b

RearrangeEqn