So for this, I will be using the substitution method. Firstly, subtract both sides in the second equation by 2x:
Next, substitute y in the first equation with 7-2x, then solve for x from there:
Now that we got x, substitute it into either equation to solve for y:
In short, x = 1/2 and y = 6.
Answer:
Maximum volume = 649.519 cubic inches
Step-by-step explanation:
A rectangular piece of cardboard of side 15 inches by 30 inches is cut in such that a square is cut from each corner. Let x be the side of this square cut. When it was folded to make the box the height of box becomes x, length becomes (30-2x) and the width becomes (15-2x).
Volume is given by
V =
First, we differentiate V(x) with respect to x, to get,
Equating the first derivative to zero, we get,
Solving, with the help of quadratic formula, we get,
,
Again differentiation V(x), with respect to x, we get,
At x =
,
Thus, by double derivative test, the maxima occurs at
x = for V(x).
Thus, largest volume the box can have occurs when .
Maximum volume =