Question

A group of students are planning a mural at a wall the rectangular wall has dimensions of (6x+7) by (8x+5) and they are planning the mural to be (x+4) by(2x+5) what is the area of the remaining wall after the mural has been Painted

Answer 1

Answer: $46x^2+73x+15$

Step-by-step explanation:

The area of a rectangle can be calculated with the formula:

$A=lw$

l: the length of the rectangle.

w: the width of the rectangle.

The area of the remaning wall after the mural has been painted, will be the difference of the area of the wall and the area of the mural.

Knowing that the dimensions of the wall are $(6x+7)$ by $(8x+5)$, its area is:

$A_w=(6x+7)(8x+5)\\\\A_w=48x^2+30x+56x+35\\\\A_w=48x^2+86x+35$

As they are planning that the dimensions of the mural be $(x+4)$ by $(2x+5)$, its area is:

$A_m=(x+4)(2x+5)\\\\A_m=2x^2+5x+8x+20\\\\A_m=2x^2+13x+20$

Then the area of the remaining wall after the mural has been painted is:

$A_{(remaining)}=A_w-A_m\\\\A_{(remaining)}=48x^2+86x+35-(2x^2+13x+20)\\\\A_{(remaining)}=48x^2+86x+35-2x^2-13x-20\\\\A_{(remaining)}=46x^2+73x+15$