2) 4:(-1/2)

To solve this proportion, multiply 4 by the reciprocal of -1/2:

4 * (-2/1) = -8

Therefore, the solution is -8.

4) (-4/2/3):2/9

To solve this expression, first simplify the division of fractions:

(-4/2/3) ÷ (2/9)
= (-4/2 3) ÷ 2
= (-2 3) ÷ 2
= -6 ÷ 2
= -3

Therefore, the solution is -3.