Answer:
7) I believe it is "The sum of the large rectangle is equal to the sum of the two smaller rectangles. 3 (x + 4)" But I am not sure.
8) Make it shorter and simpler by combining like terms
9) 5x , 2a + 3 + a + 4 , 6 + 2x + x2 + 1 + x
10) ac + bc = (a + b) c
Explanation: