Michael is X years old.
Ryan is X-4 years old.
The product of their ages is 1020:
x(x-4)=1020 multiply both terms inside () by x:
x^2-4x=1020 (subtract 1020 from both sides):
x^2 - 4x -1020 =0 (factor with reverse foil)
(x + 30)(x - 34) (set each = 0 and solve):
x+30=0 ---> x=-30 age can't be negative, so this isn't the answer.
x-34=0 ---> x=34