"Find the smallest number. . .?"
Do you mean "find the smallest 3 numbers" or "find the smallest 3 consecutive numbers" or "find the smallest 4 numbers" or what?"
If you meant "find the smallest 2 numbers," there appears to be no solution:
x + y = 38
xy = 1728
x = 1728/y
1728/y + y = 38
1728 + y^2 = 38y
y^2 - 38y + 1728 = 0
Quadratic formula:
y = (-b +- sqrt( b^2 - 4ac) ) / 2a
y = (38 +- sqrt(38^2 -4*1*1728) ) /2
y = (38 +- sqrt(1444 - 6912) ) / 2
y = (38 +- sqrt(-5468) ) / 2
Can't do the square root of a negative number, so there's no solution.