Explanation:
You multiply by 4/3 because you are essentially "dividing" both sides by 4/3. You have to take the reciprocal of 3/4 which is 4/3 in order to cancel out the 3/4 because 4/3 x 3/4 will be 1. So the problem will look like this:
(1/2)x + 2 = (3/4)y
4/3[(1/2)x + 2] = 4/3 x 3/4y
4/3[(1/2)x + 2] = y
4/6 x + 8/3 = y
y = 2/3(x) + 8/3
And then from here, if they gave a value for x and y, you can solve for the 2 variables.