SOLUTION: I could not figure this question out....3y2-2brackety-(3-2y)bracket=3(y-2)to the 2nd power -12? The choices are a)0 and -1 B)0 and -2 C)0 D)-1 E)-2 Thank you for your time.

Algebra ->  Expressions-with-variables -> SOLUTION: I could not figure this question out....3y2-2brackety-(3-2y)bracket=3(y-2)to the 2nd power -12? The choices are a)0 and -1 B)0 and -2 C)0 D)-1 E)-2 Thank you for your time.      Log On


   



Question 13954: I could not figure this question out....3y2-2brackety-(3-2y)bracket=3(y-2)to the 2nd power -12? The choices are a)0 and -1 B)0 and -2 C)0 D)-1 E)-2 Thank you for your time.
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
Let me begin by saying that I can't use brackets in algebra.com equation notation, since it has a different meaning --it's used for subscripts. Therefore, where you called for brackets, I'll have to use parentheses.
3y%5E2+-+2%28y-%283-2y%29%29=+3%28y-2%29%5E2-12
3y%5E2+-2%28y-3%2B2y%29+=+3%28y%5E2+-4y%2B4%29+-12
3y%5E2+-2%283y-3%29+=+3y%5E2+-12y+%2B+12+-+12+
3y%5E2+-+6y%2B6+=+3y%5E2+-+12y+

Subtract +3y%5E2 from each side and add +6y to each side:
3y%5E2+-+3y%5E2+-+6y+%2B+6+=+3y%5E2+-+3y%5E2+-+12y
-6y+%2B+6+=+-12y
-6y+%2B6y+%2B+6+=+-12y+%2B+6y
6+=+-6y

Divide both sides by -6, and you get
y = -1 Which would be answer D.

If you substitute the value of y=-1 back into the original equation, I think you get 15 = 15, which checks.

R^2 at SCC