Solving for x means we want to get it by itself. First, we deal with terms without x. Since we have - 4, we add 4 to both sides.
(2/5)x - 4 + 4 = 10 + 4
Since -4 + 4 = 0, we are left with...
(2/5)x = 14
To get rid of the 2/5, we multiply both sides by 5/2, the reciprocal. 2/5)(5/2) = 1, so the 2/5 "goes away" because we don't write 1x.
(5/2)(2/5)x = (5/2)14
x = 70/2 = 35
