Answer:
6x - 9(-4x + 8) = 12
Step-by-step explanation:
Solving the first eqution for y, you have
... y = -4x +8
Substituting that into the equation
... 6x -9y = 12
you have ...
... 6x -9(-4x +8) = 12 . . . . . . . matches the 3rd choice.
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Comment on the question
The given equation is 6y -9y = 12, something entirely different from 6x -9y = 12. None of the answer choices apply to the equations given in your problem statement.
