Question 178952
a-{5b-[a-(3b-2c)+c-(a-2b-c)]}


This one, I won't show so many intermediate steps and won't write all the comments. See the other problems. The ideas are the same. As they get longer, start with the grouping that most deeply embedded in the expression. Watch the signs!

a-{5b-[a+(-3b+2c)+c+(-a+2b+c)]}
a-{5b-[a-3b+2c+c-a+2b+c]}
a-{5b+[-a+3b-2c-c+a-2b-c]}
a-{5b-a+3b-2c-c+a-2b-c}
a+{-5b+a-3b+2c+c-a+2b+c}
a-5b+a-3b+2c+c-a+2b+c
a+a-a-5b-3b+2b+2c+c+c
a-6b+4c