Question

How do you factor completely: `x^2 + 10x + 25`?

Answer 1

`(x + 5)^2`

Explanation:

`ax^2 + bx + c`

Start by writing down all of the factors of c (25 in this case)
`25 = 1*25; 25 = 5*5`
now check, which of them might add up to, or have a difference of b (10 in this case)
`5+5 = 10`
so now we can insert these into the brackets:
`(x+5)(x+5)`
which is equivalent to `(x+5)^2`