Answer:
[tex]A=(x^{2}+5x-84)\ units^{2}[/tex]
Step-by-step explanation:
we know that
The area of a rectangle is equal to
[tex]A=WL[/tex]
where
W is the width of the rectangle
L is the length of the rectangle
In this problem we have
[tex]L=(x-7)\ units[/tex]
[tex]W=(x+12)\ units[/tex]
substitute
[tex]A=(x-7)(x+12)\\A=x^{2}+12x-7x-84\\A=(x^{2}+5x-84)\ units^{2}[/tex]
