How do you evaluate #-7a + 11 + 11a = -99 -(-11a) + 4a#?

1 Answer
Sep 18, 2017

#a=10#

Explanation:

#-7a+11+11a=-99-(-11a)+4a#

First, deal with the bracket on the right side. The product of two negatives is a positive:

#-7a+11+11a=-99+11a+4a#

Gather like terms on each side:

#4a+11=-99+15a#

Subtract #15a# from both sides and subtract #11# from both sides:

#4a-15a+11-11=-99-11+15a-15a#

#-11a=-110#

Divide both sides by #-11#

#(-11a)/-11=-110/-11#

#a=10#

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