Ask you math masters to help me solve a problem of solving quadratic equation of one variable The square of X - 16x - 9 = 0, how to solve it by factoring, teach me, the best process is detailed, so that I can understand, I can't just copy the answer

Ask you math masters to help me solve a problem of solving quadratic equation of one variable The square of X - 16x - 9 = 0, how to solve it by factoring, teach me, the best process is detailed, so that I can understand, I can't just copy the answer

It can not be solved by factorization
x^2-16x=9
x^2-16x+64=9+64
(x-8)^2=73
x-8=±√73
∴x=8±√73