Exercise 49 Page 533

Equations in slope-intercept form follow a certain format. y=mx+ b In this form, m is the slope and b is the y-intercept. The line has a slope of - 3 which means that we can substitute m=- 3. y=- 3x+ 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 (2,5) into the equation and solving for b.

y=- 3x+b

SubstituteII

x= 2, y= 5

5=- 3( 2)+b

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Solve for b

Multiply

Multiply

5=- 6 +b

AddEqn

LHS+6=RHS+6

11=b

RearrangeEqn

Rearrange equation

b= 11

Now that we have both the slope and the y-intercept, we can write the final equation. y=- 3x+ 11 Therefore, we obtained answer B.