Question

How do you factor the trinomial `b^2 - 15b + 56`?

Answer 1

Find a pair of factors of `56` whose sum is `15`, hence:

`b^2-15b+56 = (b-7)(b-8)`

Explanation:

Find a pair of factors of `56` with sum `15`. The pair `7, 8` works:

`7 xx 8 = 56`

`7 + 8 = 15`

Hence:

`b^2-15b+56 = (b-7)(b-8)`