Respuesta :

2(13) 13 = x

2 • 13 = 26

26-20= 6

4(2) = 6

y = 2

I first multiplied 4 times a number bigger than 20. It must equal an even number. I then multiplied 4 times a number that would equal six when doing 4•y. I subtracted the equation to check my answer.
y = 1/2x - 5

Take the original equation:

2x - 4y = 20 ---> subtract 2x
-4y = -2x + 20 ---> divide by -4
y = 1/2x - 5