Answer:
84x+50
Step-by-step explanation:
First, you would find the area of the entire square. The area of a square is LW, so you would multiply (7x+6)(7x+6). For this, I would use the FOIL method, so you would multiply the first terms which would be (7x)(7x)=14x^2. Then the outside terms, so (7x)(6)=42x. Then the inside, so (7x)(6)=42x. Finally, the last terms, 6(6)=36.
Then you would combine them, so the area of the whole square is which would equal
.
Then, the area of the smaller square is (x)(x) which would equal .
Then you would subtract the smaller square from the bigger one, so the final answer would be which you could simplify to