Exercise 15 Page 304

Direct variation equations are functions where y varies directly with x. They have a specific format. y= mx In this form, m ≠ 0. By substituting the given values for x and y into the equation, we can determine the constant of variation m.

y=mx

SubstituteII

x= 2, y= - 10

- 10=m( 2)

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Solve for m

RearrangeEqn

Rearrange equation

m(2)=- 10

DivEqn

.LHS /2.=.RHS /2.

m=- 5

Now that we have the constant of variation, we can write the function. y= - 5x Finally, we will substitute 12 for x to find the y-value.

y=- 5x

Substitute

x= 12

y=- 5( 12)

MultNegPos

(- a)b = - ab

y=- 60

We have found that y=- 60 when x=12.