Needed help solving this math problem

Question

x^2 =4x + 45

What does x=?

Answer 1

x^2 =4x + 45      given

x^2 - 4x - 45 = 0 subtract 4x - 45 from both sides

x^2 - 9x + 5x - 45 = 0 factorization

x(x-9) + 5(x-9) = 0 take out commons

x + 5 = 0 and x - 9 =0

threfore x = -5, 9

Answer 2

x^2=4x+45 x^2-4x-45=0 Moving everything to the same side is usually the best idea when x is squared (or taken to any higher exponent) Here you can either factor or use the quadratic formula. We'll try factoring, see if there are any quick and easy ones. (x+5)(x-9)=0, check by FOILing out. x^2+5x-9x-45=0 x^2-4x-45=0 therefore (x+5)(x-9)=0 is correct. So, set both equal to zero and solve for x, giving x+5=0, x=-5 x-9=0, x=9