If the question is: "<span>Find two positive numbers whose difference is 28 and whose product is 3900</span>"
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.