The answer to this question is the solution to the equation:
#4/5 - x = 2/3#
To combine the fractions, first find the least common factor of #3# and #5# by looking at the multiples of the largest number, and choosing the first one that is a multiple of the lower one. In our case, that least common factor is #15#. Then, multiply the numerator and denominator of each fraction by the same number, to get equivalent fractions with #15# in the denominator, then subtract the resulting #10/15# from both sides:
#12/15 - (15x)/15 - 10/15 = 0 => (12 - 15x - 10)/15 = 0#
#=> (2 - 15x)/15 = 0 => 2 - 15x = 0 => 15x = 2 => x = 2/15#
Note that when we have a zero on one side, we can multiply both sides of the equation with the denominator to get rid of it, since the zero "absorbs" it (#15 * 0 = 0#)
