Answer:
[tex](-7x^2+3)(x-3)[/tex]
Step-by-step explanation:
To factor by grouping, take the first two numbers and last two numbers. First, look at the first two numbers.
[tex]-7x^3+21x^2[/tex]
Each number can be divided by 7 and x^2, so pull it out as a GCF.
[tex]-7x^3+21x^2 = -7x^2(x-3)[/tex]
Next, look at the last two numbers.
[tex]3x-9[/tex]
Each number can be divided by 3, so we will pull it out as a GCF.
[tex]3x-9=3(x-3)[/tex]
Add the two results together.
[tex]-7x^2(x-3)+3(x-3)[/tex]
When factoring by grouping, the two expressions in the parenthesis should always be the same. In this case, it is x-3.
Combine the numbers outside and inside parenthesis.
[tex](-7x^2+3)(x-3)[/tex]
