1) -2x = 34
The inverse of multiplication is division, so divide both sides by -2.
x = -17
2) y - 3.5 = -2.1
The inverse of subtraction is addition, so add 3.5 to both sides.
y = 1.4
3) 2/3z = -6
The inverse of division is multiplication, so multiply both sides by 3z
2 = -18z
z = -1/9