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Factor the following polynomial:

Step-by-step explanation:

The first step is to find the GCF. Here, it's 3.

Then, you factor the polynomial in the parenthesis.

To find the factors, you will need to find 2 numbers that add to -7, and multiply to 10. -2 and -5 add to -7 and multiply to 10. Now, replace -7a with the factors.

This of this polynomial as 2 problems.

Then, factor again.

Then, you keep the factors in parenthesis, and combine the numbers on the outside.

Since, there are 2 of the same factor, you only need one.

BUT REMEMBER!! In the very beginning, we had a 3 that we took out, we STILL need to add that to the final answer. The final answer is:

3a²-21a+30

=3(a²-7a+10)

=3(a²-5a-2a+10}

=3(a(a-5)-2(a-5))

3(a-5)(a-2)