Question 630360
 A larger rectangle has another, smaller rectangle inscribed within it. 
The larger rectangle has sides given by the equation 3x2 + 7x + 6 and 5x + 4.
The inner rectangle has sides given by 2x2 + 4x + 3 and 2x + 1.
Calculate the area between the two rectangles.
:
Find the areas
d = {{{((3x^2+7x+6)*(5x+4))}}} - {{{((2x^2+4x+3)*(2x+1))}}}
dif in area = large rect area - small rec area
d = {{{(15x^3+47x^2+58x+24)}}} - {{{(4x^3+10x^2+10x+3)}}}
remove brackets
d = {{{15x^3+47x^2+58x+24 - 4x^3-10x^2-10x-3}}}
combine like terms
d = {{{15x^3-4x^3+47x^2-10x^2+58x-10x+24-3}}}
d = {{{11x^3+37x^2+48x+21}}} sq/units