Question

A cube has side length x. One side of the cube is increased by 4 inches, and another side is doubled. The volume of the new rectangular prism is 450 cubic inches. The equation 2x2 + 8x2 = 450 can be used to find x. What was the side length of the original cube?

Answer 1

Answer: B. 5.

Explanation:

It’s the right answer

Answer 2

Let the length of side of cube=x

One side length is increased by 4cm,so the length will be x+4

Another side will be doubled,so new length will be 2x

And the thIrd side will be same as it is.

So the volume of new rectangular prism will be=

x × (x+4) × 2x=450

i.e 2x³+8x²=450

dividing 2 on both sides we will get,

x³+4x²=225

i.e x=5

So original length of cube is 5inch (Answer)