A rectangle has a length of x inches and a width 3 inches less than the length. if the dimensions were doubled, what would be the area of the new rectangle in terms of x?

Original length: x

original width; x-3

original area: x (x-3)

when the dimensions doubles, that is, increase by a factor of 2, the area increase by 2²

4[x (x-3) ]

4x (x-3) = 4x²-12x

you can also do it this way:

original length: x doubled: 2x

original width; x-3 doubled: 2 (x-3)

new area:2x[2 (x-3) ] = 4x²-12x