systems of equations 3?

Question

x*x-2y=11
x=y+4
show working please

Answer 1

Not really sure what you want but I'm just going to solve x and y.
y= x-4 -1
x^2 -2y -11 = 0 -2
replace 1 in 2
x^2 -2x -3 = 0
(x-3)(x+1) = 0
thus x = 3 or x = -1
replace in 1
thus if x = 3 ; y = -1
and if x = -1 ; y = -5

Answer 2

x*x-2y=11
x=y+4

so,
(y+4)^2-2y=11
or, y^2 + 4y + 4 -2y - 11 = 0
or, y^2 +2y -7 = 0
or, y = 1.8284, 3.8284