Answer:
x = 9 ; -1
Step-by-step explanation:
[tex]x {}^{2} - 8x + 16 = 25 \\ x {}^{2} - 8x + 16 - 25 = 0 \\ {x}^{2} - 8x - 9 = 0 \\ (x + 1)(x - 9) = 0 \\ x = - 1 \\ x = 9[/tex]
