Are you solving for A? Simply cross multiply and solve for A
2a - 3 a - 1 -------- = ------- 3 2
you want to mutiply (2a -3)(2) and (a - 1)(3)
(2a - 3)(2) = (a - 1)(3) 4a - 6 = 3a - 3
Now get the a terms on the same side
a - 6 = -3
Now move the 6 over a = 3
28 and 29 are done the same way. For #30 you need to move the 1/4 from the left side to the right side before solving (so it looks like below) then cross multiply as you did in the other problems.
