Hi Humar,
Formula for area of any rectangle is:
A= LW
L=Length
W=Width
Here,
L= 4x -4
W= 11 - x
A(x)= (4x-4)(11-x)
Foil that:
A(x) = 44x - 4x2 -44 + 4x
Rearrange in descending order and combine like terms:
A (x)= -4x2 + 48x - 44
You can leave like this or factor out a -4--not sure how far your teacher wants you to go on simplification but if you factor out a -4:
A(x) = -4(x2 - 12x +11)
Factor the inside:
A(x) = -4(x-11)(x-1)
Again, not sure how far your teacher wants you to simplify, but all are viable expressions for the area, and the last is as simplified as can be. I hope this helps.