Question

^ please help me____________

Answer 1

All you have to do is take half of 6x, square it and add it to both sides. It will look like this. x^2+6x+9=16+9. Now all you do is simplify to get (x+3)^2=25.

Answer 2

X^2 + 6x - 16 =0
The two numbers that satisfy the condition quadratics have is
1. They must add to 6
2, They must multiply to - 16 

All quadratics have to satisfy these two things.
The only numbers that will are 8 and - 2
So the factors are
(x - 8)(x + 2) = 0
x - 8 = 0
x = 8

and

x + 2 = 0
x = - 2