Question

Factor the Expression x^2-15x+54

Answer 1

can you think of two factors (positive or negative) of 54,
that add to -15?

Answer 2

9 & 6

Answer 3

right, but we want them to add to negative 15,

Answer 4

-9 +-6

Answer 5

yeah,

so x^2-15x+54=(x-9)(x-6)

now if you want to check it (and you should)

expand the brackets in your answer
(x-9)(x-6)=x(x-6)-9(x-6)
= x^2-6x-9x+54

Answer 6

which should simplify to the original expression in the question

Answer 7

thank you! i understand so much better now!

Answer 8

\[\Large\ddot\smile\]