
We want to find factors of 10 that sum to negative 7. Well, the two factors must

be negative 2 and negative 5. We can rewrite the middle term using minus 2x and

minus 5x, from these factors. Then, we do our factoring by grouping and our

final answer is x minus 5 times x minus 2. This stuff right here is the

trickiest part. We need to factor out a negative 5 from both of these terms. If

I factor out a negative 5 from positive 10, I'm left with negative 2. Remember

that you can check your work by distributing. This allows us to be sure that

we've done factoring by grouping correctly. Moving this way would be factoring,

so if we distribute, we would be undoing that process. Nice work with your

negative numbers and your factoring if you got that one correct.