Solve "x^2 - 12x - 45 = 0" by completing the square

The equation is of the formx²+bx+c=0This means it can be rearranged to(x+(b/2))²=(b/2)²-cTaking the square root of both sides leaves us with x.
x²-12x-45=0(x-(12/2))²-(12/2)²-45 = 0(x-6)²-6²-45 = 0(x-6)² = 45 + 36(x-6)² = 81x-6 = 9x= 6 + 9 = 15