Answer:
(3)(x+7)(x-1)
Explanation:
3x^2+18x-21
Let's start by taking 3 out of the equation.
3(x^2+6x-7)
Now, when we factor, we need to find two numbers that add up to 6 and multiply to -7.
The numbers would be 7 and -1.
So the factored form of this would be:
(3)(x+7)(x-1)