Question

a rectangle has a length of x+7 and a width of x-3. Which equation below describes the area, A, of the rectangle in terms of x ( number 30)

Answer 1

It is given that a rectangle has a length of l=x+7 and a width of w=x-3.

Hence the area of rectangle is given by:

$\begin{gathered} A=l\times w=(x+7)(x-3)=x\mleft(x-3\mright)+7\mleft(x-3\mright) \\ A=x^2-3x+7x-21 \\ A=x^2+4x-21 \end{gathered}$

Hence option A is correct.