Answer:
x = -5 or +5
Step-by-step explanation:
Subtract 16 and factor.
x^2 -9 = 16 . . . . . given
x^2 -25 = 0 . . . . subtract 16; the difference of squares
(x -5)(x +5) = 0 . . . . the factored form
The zero product property says possible solutions are found where the factors are zero.
For (x -5) = 0
x -5 = 0
x = 5 . . . . . add 5
For (x +5) = 0
x +5 = 0
x = -5 . . . . . subtract 5
Possible solutions are x=-5 or x=5.
