X^2-x-20 how do I write that in factored form

( x - 5 ) ( x + 4 )

Step-by-step explanation:

When solving quadratic equations it's important to remember that they have 2 solution. We need to work out the factors, sum and the products to successfully factorise the quadratic and solve it. So,

x² - x - 20 = 0

Sum = -1

Product = -20

So we need two numbers that sum to -1 and multiply together to make -20

Factors = -5 and 4

x² - 5x + 4x - 20

Factor x² - 5x and 4x -20 separately

x² - 5x = x ( x - 5 )

4x - 20 = 4 ( x - 5 ) So

x ( x - 5 ) + 4 ( x - 5 )

We can see a common factor of  ( x - 5 ) and the other bracket would be       ( x + 4)

( x - 5 ) ( x + 4 )