If possible, completely factor the expression. (If the polynomial is not factorable using integers, enter PRIME.)
x^2 - 4x - 5
= _____
(x-5)(x+1)
To completely factor the expression x^2 - 4x - 5, we need to find two numbers that multiply to -5 and add up to -4.
Listing down the factors of -5, we get:
1 and -5
-1 and 5
Out of these options, the combination that adds up to -4 is 1 and -5.
So now we can rewrite the expression using these numbers:
x^2 - 4x - 5 = (x - 5)(x + 1)
Therefore, the expression x^2 - 4x - 5 can be completely factored as (x - 5)(x + 1).