What is the volume of a box whose length is 12-2x, width is 7-2x, and height is x.

l*w*=height
12*7=84
2x=84
x=42

Is this right, check for me please

volume = (12-2x)(7-2x)(x)

then you say ...
l*w*=height
12*7=84
2x=84
x=42

I haven't got the foggiest idea what that is supposed to be.

To find the volume of a box, you need to multiply the length, width, and height of the box together.

In this case, the length of the box is given as 12-2x, the width is 7-2x, and the height is x.

So, the volume (V) of the box can be calculated as V = (12-2x) * (7-2x) * x.

To check if the calculation is correct, let's substitute x=42 into the equation and calculate the volume:

V = (12-2*42) * (7-2*42) * 42

First, simplify the equation inside the parentheses:

V = (12-84) * (7-84) * 42

V = (-72) * (-77) * 42

Next, multiply the values together:

V = 5544 * 42

V = 232848

Therefore, the volume of the box is 232848 cubic units.

Please note that there seems to be an error in your calculation where you assumed 2x is equal to 84, which led to an incorrect value for x. The correct value for x is 42.