Please use " ^ " to denote exponentiation: y=x^2+5x−7.
Borrow "x+5" from the first equation and replace y in the second with that:
x+5 = x^2 + 5x - 7. Then x^2 + 5x - 7 - x - 5 = 0, or x^2 + 4x -12 = 0.
This is easily factored: (x-2)(x+6)=0, so that x=2 and x=-6.
Using y = x+5, find y for x=2 and then y for x=6.
