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If y = -9 when x = 3, find y when x = -6. when x = -5.

User Wodin
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1 Answer

27 votes
27 votes

Answer:

When x is -6, y will be 18

When x is -5 y will be 15

Explanation:

Create a proportion

y/x

-9/3 = x/-6 What do we need to multiply 3 by to get 6? -2, so we will multiply -9 by -2 to get 18

Some people like to solve by cross multiplying.

That would give us

(-9)(-6) = 3x

54 = 3x divide both sides by 3

18 = x

Set up the second problem as a proportion

-9/3 = x/-5 This is a little trickier. I am trying to think what I have to multiply 3 by to get -5. 3(-5/3) will give me -5, so I will multiply the top number that I know (-9) by (-5/3) to find my x.

(-9)(-5/3) = 45/3 or 15

User Bladito
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