Calculus HELP finding 2 numbers difference

Question

Find two numbers whose difference is 92 and whose product is a minimum

Answer 1

X-Y = 92

The product is Y( Y+92) = f(Y)

Y^2 + 92Y

0=dF/dY = 2Y + 92

Y = -92/2 = -46

X-Y=92

X -(-46) = 92

X+46 = 92

X = 46

46 and -46