Question

Solve by factoring the trinomial as a binomial square and then use the square root method. Round to the nearest tenth, if necessary.
x2 + 16x + 64 = 81

Is it (-17, 1)? I get that but im not sure if its right.

Answer 1

x^2 + 16 x - 17 = 0
(x - 1)(x + 17) = 0
roots are -17 and +1 as you got

Answer 2

also
( x + 8)^2 = 81
x + 8 = +- 9
x = -17 or 1