SOLUTION: Expand (s-3v)^5 I got the solution s^5-15s^4v+90s^3v^2-270s^2v^3+405sv^4-243v^5 which I know is correct, but they are looking for another solution as well and it's not even someth

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Question 577885: Expand (s-3v)^5
I got the solution s^5-15s^4v+90s^3v^2-270s^2v^3+405sv^4-243v^5 which I know is correct, but they are looking for another solution as well and it's not even something with parentheses. It's one of theses three options:
Please help! :)
s^5-5s^4+90s^3-270s^2+405s-243
s^5+45s^4v-270s^3v^2+810s^2v^3-1215sv^4+729v^5
s^5-5s^4v+10s^v^2-10s^2v^3+5sv^4-v^5
Found 3 solutions by jim_thompson5910, richwmiller, KMST:
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website!
You have the correct answer. None of those answer choices are correct as there is only one correct answer. So there may be a typo.

Answer by richwmiller(17219)   (Show Source):
You can put this solution on YOUR website!
none of the three
Your answer s^5-15s^4v+90s^3v^2-270s^2v^3+405sv^4-243v^5 is correct

Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website!
You are right. The other 3 options are wrong.
s^5-5s^4v+10s^v^2-10s^2v^3+5sv^4-v^5 = (s-v)^5,
s^5+45s^4v-270s^3v^2+810s^2v^3-1215sv^4+729v^5 is a ridiculous options because the signs of the terms do not alternate properly, and
s^5-5s^4+90s^3-270s^2+405s-243 does not even include v.
For more confirmation, make s=v=1
You should get (1-3(1))^5=(1-3)^5=(-2)^5=-32
Your solution gives you
1-15+90-270+405-243=-32
The other 3 give you
1-5+90-270+405-243=-22
1+45-270+810-1215+729=100, and
1-5+10-10+5-1=0
If this is an online course, you have my sympathies. My son had some horrible online courses full of typos in the test materials.
Even high school textbooks sometimes have mistakes too.