answer: x=+/- square root of y+5 (A, i think this one kinda confused me)
y=x^2-5
substitute y for 0
0=x^2-5
subtract x^2 on both sides
-x^2=-5
since they both can be negative and positive change signs to positive to be easier
x^2=5
square root both sides
x=+/- square root of 5