Question

Use the formula 7x-5y=-12 to find y if x=3.

Answer 1

7(3) -5y =-12
21 -5y =-12
C.L.T
-5y = -12-21
-5y = -33
Divide all through by the co-efficient y
6.6

Answer 2

6
`(3)/(5)`

Explanation:

7x - 5y = -12 Substitute 3 for x

7(3) - 5y = -12

21 - 5y = -12 Subtract 21 from both sides

21 - 21 - 5y = -12 -21

-5y = -33 Divide both sides b y -5

`(-5y)/(-5)` =
`(-33)/(-5)`

y =
`(33)/(5)` or 6
`(3)/(5)`

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