Collect like terms
2y - y

The answer is y

Step-by-step explanation:

2y−y

=2y−1y

=2y+−1y

=y+y+−y

=y

9 inches long is the box.

Step-by-step explanation:

Volume of a cube is given by:

where, s is the side of the cube

Volume of a box(V) is given by:

          .....[1]

where

l is the length , w is the width and h is the height of the box respectively.

As per the statement:

The number of one-inch cubes that will fit into a box that is 6 inches wide and one inch tall is 54.

Volume of one box = in.

then;

Volume of 54 box = 54 inches.

It is also given:

w = 6 inches and h = 1 inch

Substitute in [1] we have;

⇒

Divide both sides by 6 we get;

or

therefore, 9 inches long is the box.