can someone help me

 – 8  – 9      add 9 to both sides

x^2  - 8x   = 9
Take 1/2 of the coefficient on x.... (1/2)(8) = 4 .....square this = 16, and add this to both sides   ....  so we have

 

x^2 - 8x + 16  = 9 + 16   factor the left side, simplify the right

(x - 4)^2   = 25

Take the positive and negative roots on both sides

 (x - 4) = ±√25    simplify

x - 4 = ±5    add 4 to both sides

x = ±5 + 4

 

So, x = 5 + 4  = 9      or  x = -5 + 4  = -1

(This is the same result we would have obtained by factoring directly.)