a² - 9a + 20
Factorization!
The sum is: -9
and the product is: 20
Since the sum is negative, the numbers that gave the outcome will be negative because the product is positive as well.
What and what adds to gives us -9?
What and what multiplies to give us 20?
-10 + 1 gives us -9
But the product will be -10 × 1 = -10 (its incorrect)
-4 - 5 = -9
(-4) × (-5) = 20
These satisfy both the sum and the product.
The expression will be:
(a - 4)(a - 5)
