SOLUTION: This is from the Compass sample test. Algebra Placement Polynomials 5.Which of the following is equivalent to 3a+4b-(-6a-3b)? the answer is 9a+7b Why did the the probl

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: This is from the Compass sample test. Algebra Placement Polynomials 5.Which of the following is equivalent to 3a+4b-(-6a-3b)? the answer is 9a+7b Why did the the probl      Log On


   

Question 101334: This is from the Compass sample test.
Algebra Placement
Polynomials
5.Which of the following is equivalent to
3a+4b-(-6a-3b)?
the answer is
9a+7b
Why did the the problem expand to 3a+4b+6a+3b? I do not remember the rules for this.
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
3a+4b-(-6a-3b) = 3a+4b+6a+3b because the negative sign in front of the parentheses indicates that, when you remove the parentheses, you should multiply every term within the parentheses by -1 and so, -1(-6a) = +6a and -1(-3b) = +3b, so you get:
3a+4b+6a+3b = 9a+7b