3-2x-x^2=y Given x = 2

Y = -5.

3-2(2) - 2^2 = y
3 - 4 - 2^2=y
3-4-4=y
-5=y

In simplified form, your answer would be 3+2 x 2-2^2 or in other words -3, steps:

3 - 2*2 - 2^2 = y

1 - 2 ^ 2 = y

1 - 4 = y

1 - 4 = -3/ negative three