Algebra Examples

a^{2} - a - 20

$a^{2} - a - 20$

Step 1

Consider the form

x^{2} + b x + c

$x^{2} + b x + c$ . Find a pair of integers whose product is

c

$c$ and whose sum is

b

$b$ . In this case, whose product is

- 20

$- 20$ and whose sum is

- 1

$- 1$ .

- 5, 4

$- 5, 4$

Step 2

Write the factored form using these integers.

(a - 5) (a + 4)

$(a - 5) (a + 4)$