Simplifying expressions

-2a + 3a + 5b

5a - 2 - 3a + 7

7x + 4 - 5x - 8

4a - 6 - 2(a - 1)

x + 5(6 + x)

-x - 2y -8x -2y

2a + 3(2 + a)

-3(6 - 2r) -3r

2(x-y) + 3x

-4(3m + 2n) -5m + n

Find an expression for perimeter

2(x - y) - (x + y)

7(3a-2b) +5b - 3(4a + 2)

-(8x + 7y - 6)