Exercise 1 Page 281

Equations in slope-intercept follow a certain format. y=mx+ b 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 (- 4,2) into the equation and solving for b.

y=- 3x+b

SubstituteII

x= - 4, y= 2

2=- 3( - 4)+b

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Solve for b

MultNegNegOnePar

- a(- b)=a* b

2=12+b

SubEqn

LHS-12=RHS-12

- 10=b

RearrangeEqn

Rearrange equation

b=- 10

Now that we have both the slope and y-intercept we can write the final equation. y=- 3x+( - 10) ⇔ y=- 3x - 10