could someone teach me a simple way for transforming formulas.

i know how to do the simple transforming of formulas, but these kinds i get confused and stuck.

examples.

EDIT:

1. a = v - u/t ; solve for u

2. a = a + b + c + d/4 ; solve for b

3. 2ax + 1 = ax + 5 ; solve for x

4. m = x + y + z/3 solve for x

5. D = a/2 (2t - 1) ; solve for a

i wouldnt want the answers to these questions,

just simple steps so i may remember to do them easily in the future.