Question

How do you factor the expression `3x^2-3x-18`?

Answer 1

Take three common and then find the roots of the quadratic equation.

Explanation:

`3x^2-3x-18=3(x^2-x-9)`
for the quadratic equation `x^2-x-9=0` a=1, b=-1, c=-9
`x=(-b+-sqrt(b^2-4ac))/(2a)`
`x=(1+-sqrt(37))/2`
therefore
`3x^2-3x-18=3(x-(1+sqrt(37))/2)(x-(1-sqrt(37))/2)`