Answer: The real solutions of the given equation are x= 1, 4, and 5.
I think its just.1for 1,2,4,7,14,28 an 1,3,5,35
The question is worded poorly, but it looks like you have a lever in equilibrium, with a force x at a distance d from the fulcrum, and a force y at a distance L - d from the fulcrum. You already have the equilibrium formula for this situation:
xd = y(L - d)
If you know x, y, and d, you can solve for the length L.
Xy=12
xdy/dx + y = 12
xdy/dx = 12 - y
dy/dx= (12-y) /x
dy/dx | x=-4 ,y=-3 = (12-(-3))/(-4)
= (12+3)/-4 = -15/4