The formula for rectangle area is #A = l * w#. This means that the Area of the rectangle is equivalent to the width and length (or height) of the rectangle.
Since we already know that the width is #4x#, and the height is #7/3 x#, we can plug these into the formula. Our formula now looks like #A = 4x * 7/3 x#.
We also know that #x=6#. Plugging in #6#, for our #x# in the equation, we get #A= 4(6) * 7/3 (6/1)#. I have put our #6# into fraction form since that is how we multiply fractions, numerator times numerator, and denominator times denominator. This leaves us with #A = 24 * 42/3#. We can divide #42 -: 3# to get our decimal value, which comes out to be #14#.
Now all that is left to do is to multiply #24 * 14# to get our area.
#A = 24 * 14 => A = 336#