You do whatever you need to do to one side of the equation in order to have
only ' y ' left on that side, AND every time you do something to that side of
the equation, do exactly the same thing to the other side.
Here are three examples, out of the 9 answers you want handed to you:
#16: 3x + 5y = 7
Subtract 3x from each side: 5y = -3x + 7
Divide each side by 5 : y = -3/5 x + 7/5
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#17: 13 = 12x - 2y
Add 2y to each side: 2y + 13 = 12x
Subtract 13 from each side: 2y = 12x - 13
Divide each side by 2 : y = 6x - 13/2
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#22: 1/4 y + 3 = -5x
Subtract 3 from each side: 1/4 y = -5x + 3
Multiply each side by 4 : y = -20x + 12