Factor x2 – 8x + 15. which pair of numbers has a product of ac and a sum of b?

Pair of numbers: -3 and -5

Factors : (x-5)(x-3)

Step-by-step explanation:

Given:

We need to factor it using AC method.

For equation:

For factor this ac and sum b

For our equation: a=1, b=-8 and c=15

Therefore,

Product = ac = (1)(15) = 15

We need to choose two number whose product is 15 and sum -8

First we find all the factor of 15: 1x15    3x5    

If we take 3x5

Product:  (-3)(-5) = 15

Sum:          -3-5  = -8

Pair of numbers: (-3,-5)

Now we will factor it.

The factors are (x-5) and (x-3)