A, it's always true
remember commutative property
a+b=b+a
a and b can be negativ numbers
so equatinos
-5.2+7.71=2.51
7.71-5.2=2.51
-8.65+3.94=-4.62
3.94-8.65=-4.62
B.
-5.2-7.71=-12.91
7.71-(-5.2)=12.91
-8.65-3.94=-12.59
3.94-(-8.65)=12.59
always false
C. when you change the order, you are subtracting a different number from a different number than before
Answer:

Step-by-step explanation:

I am joyous to assist you at any time.
Answer:
x=19
Step-by-step explanation:
Answer:
4 ounces = 1/4 lbs (pounds) 1/3 of 66 is 22
The answer is 7x = 6(x + 15)
x - Jim's rate
y - Pete's rate
<span>Jim completed half the floor in 7 hours: 7x = half of the floor
</span><span>Pete completed the other half of the floor in 6 hours: 6y = half of the floor
So: 7x = 6y
</span><span>Pete can lay 15 more tiles per hour than Jim: y = x + 15
</span>7x = 6y
y = x + 15
Substitute the second equation into the first one:
7x = 6(x + 15)