1) 10 + x = -20 + (-5)

10 + x = -20 - 5

10 + x = -25

x = -25 - 10

x = -35

2) -12 + x = -11 - (-10)

-12 + x = -11 + 10

-12 + x = -1

x = -1 + 12

x = 11

3) -16 - x = 32 - (-12)

-16 - x = 32 + 12

-16 - x = 44

-x = 44 + 16

-x = 60

x = -60

4) x + (-18) = -29 - (-19)

x - 18 = -29 - 19

x - 18 = -48

x = -48 + 18

x = -30