Answer:
[tex]3n^2+3n-6=54[/tex]
Step-by-step explanation:
Total Area=54 square inches. Area=length*width.
Because the length is [tex][3(n-1)][/tex], and the width is [tex](n+2)[/tex], you can plug that into the equation for area. In this case, because the total area is 54, we can plug that in for area.
[tex][3(n-1)](n+2)=54[/tex]
Distribute through the parenthesis in [tex]3(n-1)[/tex].
[tex](3n-3)(n+2)=54[/tex]
Then, multiply [tex]3n-3[/tex] and [tex]n+2[/tex] using whatever method you prefer. I used FOIL, which stands for First, Outer, Inner, Last. You multiply the first terms together, the outer terms together, the inner terms together, and the last terms together.
[tex]3n^2+6n-3n-6=54[/tex]
Simplify.
[tex]3n^2+3n-6=54[/tex]