How do you factor the expression $3x^2 - 6x - 9$ ?

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Answer 1 · 2018-03-10T18:46:46

$=3(x+1)(x-3)$

$3x^2-6x-9$
$=3(x^2-2x-3)$ (taking out the common factor of 3)
$=3(x+1)(x-3)$ ("looking for factors of 3 to give -2")

Answer 2 · 2018-03-10T18:50:27

$x=3$ and $x=-1$

All terms have a $3$ in common, so we can factor this out. When we factor out a $3$ , we are essentially dividing every term by $3$ . We get:

$3(x^2-2x-3)=0$

Now, we can factor the inside, if we think of two numbers, when I add them, add up to $-2$ , and those same two numbers have a product of $-3$ .

$-3+1=2$ , and $-3*1=-3$ , therefore $-3$ and $1$ are our two factors. We get:

$3(x-3)(x+1)=0$

We can simplify this further by setting every term equal to zero and we get two solutions:

$x=3$ and $x=-1$

How do you factor the expression 3x^2 - 6x - 93x^2 - 6x - 9?