How do you factor x2 plus 16-8x?

Answer 1

x2 + 16 - 8x is a perfect square. First, let's correctly arrange the terms:

= x2 - 8x + 16

We can see that the last term is equal to the square of half the coefficient of the second term. This tells us that it's a perfect square, and we can simply say:

= (x - 4)2

We can also work this out using the usual technique for finding factors of quadratic expressions. We need two numbers that add to make -8 and multiply to make 16. That would be two of the same number, -4.:

= x2 - 4x - 4x + 16

= x(x - 4) - 4(x - 4)

= (x - 4)(x - 4)

= (x - 4)2