If a trinomial is of the form

(so 1 in front of x-squared, a number in front of x and a single number)

then you can factorise the formula with double brackets

For the numbers on the dots you should find two numbers so that:

.... + .... = b the **sum** of the two numbers in the number in front of x

.... x .... = c the **product** of the two numbers is the single number