If the question is:
"Find two positive numbers whose difference is 28 and whose product is 3900"
If the larger number is x, then
x-3900/x=28
multiply by x and transpose
x^2-28x-3900=0
Factor
(x+78)(x-50)=0
Using the zero product property,
x=-78 or x=50, ie. x=50, y=-78
NOTE: if question requires both numbers be positive, there is no solution.
