Combine like terms

Question

Combine like terms

anonymous · Answer

$$(7x ^{3} - 12x ^{2} - 7) + (6x ^{2} - 9)$$

anonymous · Answer

Basically, add the polynomial. I thought I had the right answer, but the answer key is telling me otherwise. I think the answer key is wrong.

anonymous · Answer

What did you get on the answer key?

anonymous · Answer

The answer key says 7x^3 - 7. It is probably right, they usually are, but I just don't see it.

anonymous · Answer

My answer was $$7x ^{3} -6x ^{2} - 16$$

jdoe0001 · Answer

$\bf (7x ^{3} - 12x ^{2} - 7) + (6x ^{2} - 9)\implies 7x ^3 - 12x ^2 - 7+6x ^2 - 9\ \quad \
7x ^3 \color{blue}{- 12x^2+6x^2} \color{green}{- 7 - 9}$

jdoe0001 · Answer

$\bf 7x ^{3} -6x ^{2} - 16$   is correct

anonymous · Answer

So, the answer key is incorrect?

jdoe0001 · Answer

yeap,  unless you  have a typo somewhere

jdoe0001 · Answer

hmm url needs a login

anonymous · Answer

Here was its reasoning, but the equation they showed was totally different from the one asked.

anonymous · Answer

attachment

anonymous · Answer

But the equation it showed was the one I originally showed in the question in the same matter.

jdoe0001 · Answer

hmm maybe you have the wrong number match to the answers

maybe say is exercise 11 and you're looking at answer 12 or so

jdoe0001 · Answer

because they look totally different

jdoe0001 · Answer

ohh ... well, the 2nd line ... .I see... lemme do it

anonymous · Answer

(4x^4 - 8x^2 - 11) - (5x^4 + 2x^2 - 14)

What do you get for this problem? I can't seem to get the right one on this either. I think it is another typo.

anonymous · Answer

$$(4x ^{4} - 8x ^{2} - 11) - (5x ^{4} +2x^{2} - 14)$$

jdoe0001 · Answer

$\bf -x^4-10x^2+3$

anonymous · Answer

Same here. Okay, I think there are typos going on in the course. Thanks!

jdoe0001 · Answer

yw