Answer: 20 pounds of peanuts and 80 pounds of cashews.
X-y=-1
x+y=5
y=x+1
x+x+1=5
2x+1=5
2x=4
x=2
y=x+1
y=2+1
y=3
The vol. of a cube of side length s is V=s^3.
So, if the side length is 5a+4b, then the volume of the cube is
V(a, b) = (5a+4b)^3. This could, of course, be expanded, using the binomial theorem, but there's no point in doing so.
