a) a-[b-(a+c)]
b) 6x-[y-(3y-7x+6)-1]
a-[b-(a+c)]
a-[b-a-c]
a-b+a+c
2a-b+c
6x-[y-(3y-7x+6)-1]
6x-[y-3y+7x-6-1]
6x-[-2y+7x-7]
6x+2y-7x+7
-x+2y+7
Comments
a-[b-(a+c)]
a-[b-a-c]
a-b+a+c
2a-b+c
6x-[y-(3y-7x+6)-1]
6x-[y-3y+7x-6-1]
6x-[-2y+7x-7]
6x+2y-7x+7
-x+2y+7