So basically, these questions want you to find the variable<em> x</em>, which you can do by isolating the variable.
3) x * 1/2 = 1/3 <-- To isolate the x in this case, you want to divide both sides by 1/2, aka multiply by 2.
x = 2/3
4) x * 3 = 2 <-- To isolate x, you want to divide both sides by 3
x = 2/3
5) 1/4 * x = 1/6 <-- To isolate x, you want to divide both sides by 1/4, aka multiply by 4.
x = 4/6 = 2/3
6) 4 1/2 * x = 1 1/2 <-- First, let's make these into improper fractions
9/2 * x = 3/2 <-- To isolate x, you want to divide both sides by 9/2, or multiply both sides by 2/9
x = 6/18 = 2/3
