Question

Factor completely x2 + 20x − 36.

Answer 1

Answer:

Prime

Step-by-step explanation:

x² + 20x − 36

You must find a pair of numbers that multiply to give -36 and add to give +20.

The likely candidates are 2 and 18, and they must have opposite signs to give a negative product.

+2 × (-18) = -36; +2 + (-18) =   -16

-2 ×   18  = -36;  -2 +     8   = +16

Neither combination gives +20 as the sum.

The expression can't be factored with rational numbers.

The expression is prime.