Step-by-step explanation:

I think, he made a mistake because the exponents have different values but then if you'll look at his results, he just wrote the same thing. If you want, you could post the original problem, and I'll solve it for you :)
Earned Income because she is working full time, but also adds the extra 20$ for when she tutors in her free time<span />
C is the correct answer using scientific notation Hope this helps! :D
Answer:
-20n^2-39n-15
Step-by-step explanation:
The last one if I'm not mistaking