If the area of a rectangle is 3x^2 + 12x, and the width is 3x, what is the length?

Answer 1

Remember that the area of a rectangle can be expressed as

Area = (Length)(Width)

or

A = (L)(W)

So let's plug in the values given to us,

A = 3x^2 + 12x and W = 3x

This gives us,

3x^2 + 12x = (L)(3x)

Now let's solve for L by dividing both sides by 3x,

x + 4 = L

So the length is x + 4