Explicație pas cu pas:
a) x + 16-30= -5
x +16= -5 +30
× +16 = 25
x = 25 -16
× = 9
b) -(2-3) + x = 21
-2 +3 +× = 21
1 + x = 21
x = 21 - 1
x = 20
c) x-(6-4) =0
x - 2 = 0
x = 2
d) x + (-5+1)-6=-1+9
x - 5 +1 - 6 = 8
x - 5 +1 = 8+6
× -5 +1 = 14
x-5 = 14 -1
× - 5 = 13
x = 13 +5
×= 18