Factorise: a squared - 9a + 20? What are all the steps?

First, factorise the quadratic equation a^2 - 9a + 20 Find two numbers which add up to 9 and multiply to give 20. These numbers are 4 and 5. (a - 4) (a - 5)

Does that make sense?

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)