The associative property of addition is pretty much just any numbers in place of these: a + (b + c) = (a + b) + c. Therefore, your answer would be d) (6 + 1) + 9 = 6 + (1 + 9)
Answer:
The third one
Step-by-step explanation:
4m = 12x + 40
8x + 8x + 12x + 40 + 4m = 360
28x + 40 + 12x + 40 = 360
x = 7
m = 12(7) + 40 = 124
Use Pythagorean Theorem which states that in a right triangle:

, where a and b are the legs, and c is the hypotenuse.

Take the square root of both sides to solve for x.

The answer is 26.
32 students in 1 row
16 students in 2 rows
8 students in 4 rows
4 students in 8 rows
2 students in 16 rows