4a+3b-2(a-5)+6b-7
= 4a+3b-2a+10+6b-7
= (4a-2a)+(3b+6b)+(10-7)
= 2a+9b+3

8x-(2x+5)+3(1-x)+12
= 8x-2x-5+3-3x+12
= (8x-2x-3x)+(-5+3+12)
= 3x+10

2(3m-4n+5)-(m-2n-7)
= 6m-8n+10-m+2n+7
= (6m-m)+(-8n+2n)+(10+7)
= 5m-6n+17

9p-[4p-(3-p)]+2
= 9p-(4p-3+p)+2
= 9p-(5p-3)+2
= 9p-5p+3+2
= 4p+5

(6c-9d+4)+(3d+7-2c)
= 6c-9d+4+3d+7-2c
= (6c-2c)+(-9d+3d)+(4+7)
= 4c-6d+11

(-5x+3y-8)+(11x-2y+1)
= -5x+3y-8+11x-2y+1
= (-5x+11x)+(3y-2y)+(-8+1)
= 6x+y-7

(a-2b+3c)+(4a+b-c+6)
= a-2b+3c+4a+b-c+6
= (a+4a)+(-2b+b)+(3c-c)+6
= 5a-b+2c+6

(2g+5h-4)-(7g-3h+12)
= 2g+5h-4-7g+3h-12
= (2g-7g)+(5h+3h)+(-4-12)
= -5g+8h-16

(4-3m+8n)-(10m-6+n)
= 4-3m+8n-10m+6-n
= (-3m-10m)+(8n-n)+(4+6)
= -13m+7n+10

(3p-4q+7r-9)-(5p+2q-r)
= 3p-4q+7r-9-5p-2q+r
= (3p-5p)+(-4q-2q)+(7r+r)-9
= -2p-6q+8r-9