I guess by V = l*w*h you mean volume = length*width*height
To find w or the width, you need to have the values for volume, height and length.
As V = l*w*h, divide both the sides of the equation by length*height
=> V/(l*h) = (l*w*h)/(l*h)
=> V/(l*h) = w
The width can be determined by dividing the volume (V) by the product of length (l) and height (h).
Divide both sides by l & h. You get w=V/(hl)
Well if the equation is V=lwh and you want to solve the equation to find the value of w, then u need to isolate the variable w to one side of the equation. You can do that by dividing the variables that are next to it so that they can be moved to the other side of the equation so that w will be alone. So:
V/(h*l)=w <--- Here the w is isolated on the right side of the equation. Now you can plug in your values and find out what w is.