Question

Factor the equation x^2-3x-18

Answer 1

Answer:

This is a Non-Perfect Square Trinomial. To factor this type of trinomial, you have to remember this pattern:

$(x+b)(x+b)=x^2+(a+b)x+ab$

So you need to find two numbers $a \ and \ b$ such that the product is $ab$ and the middle  term is the sum $(a+b)$. From our polynomial:

$x^2-3x-18$

Those numbers are:

$a=-6 \\ \\ b=3$

Because:

$ab=(-6)(3)=-18 \\ \\ a+b=-6+3=-3$

So:

$\boxed{x^2-3x-18=(x-6)(x+3)}$