Please help im so confused. (Subtracting Polynomials)

Question

narissa · Answer

attachment

narissa · Answer

at first i got 2y-4y+9 now i got -2y-4y-1...

narissa · Answer

@mathmachine090

anonymous · Answer

ok first you gotta separate the similar ones. $$y ^{2}-(-3y ^{2}$$)

narissa · Answer

so 1-(-3) right?

stamp · Answer

$$(y^2-7y-5)-(-3y^2+3y-4)$$We have a negative in front of the second parenthesis group, so begin by distributing the negative to each term.

anonymous · Answer

yeah what he said

narissa · Answer

i got C is that correct?

narissa · Answer

4y^2-10y-1? @mathmachine090

mathmale · Answer

stamp was right:

(y^2-7y-5)-(-3y^2+3y-4)

Leave the quantity in the left pair of parentheses as is.  Multiply everything within the right pair of parentheses by -1:  -1(-3y^2+3y-4).  Could you do this now, please?

narissa · Answer

yea ok 3y^2-3y-4

anonymous · Answer

i would say that C is the most accurate choice of answers right now

mathmale · Answer

Your result:   3y^2-3y-4
Expected:     3y^2-3y +4          Why the difference?

Once you're satisfied with this (and have chosen the result that is correct),   ADD these 3 
terms to    y^2-7y-5  .    Please show your work and final answer.

mathmale · Answer

Combine:

   y^2 -7y  -5
 3y^2 -3y +4 
------------
          ?

narissa · Answer

|dw:1458785005986:dw|  @mathmale