what does 4y + 8x = 16 when x equals -2 and 3

Answer 1

I presume that you meant "what does y equal when".

4y + 8x = 16

Subtract 8x from both sides:

4y = 16 - 8x

Divide both sides by 4:

y = 4 -2x

If x = -2,

y = 4 - 2(-2) = 4 + 4 = 8

If x = 3,

y = 4 - 2(3) = -2.

You can (and should!) substitute these values back and see that they are the correct solutions. If the are, then the equation 4y + 8y = 16 will hold true.