Answer:
The correct option is (d)-He wrote commutative instead of associative in Step 2.
Step-by-step explanation:
Commutative property: 
Associative property:
Now consider the provided expression.
(6.2 − 1.6) − 4.4 + 7.8
Step 1
(6.2 − 1.6) − 4.4 + 7.8
Step 2 Use Associative property
6.2 + (−1.6 − 4.4) + 7.8
Step 3: Simplify
6.2 − 6 + 7.8
Step 4: Use commutative property
14 − 6
Step 5: Simplify
14 − 6 = 8
Hence, the wrong step is step 2. He wrote commutative instead of associative in Step 2.
Therefore, the correct option is (d)-He wrote commutative instead of associative in Step 2.
Answer:
315
Step-by-step explanation:
because 15% of 2,100 is 315
Both numbers have the variable x so you add 5 and 12 which gives you 17 and you need to write the variable. The answer is 17x
3x + 7 = -x - 1
3x + 7 + = -1
4x + 7 = -1
4x = -1 - 7
4x = -8
x = -2
1 - 2x + 5 = 4x - 3
-2x + 6 = 4x - 3
6 = 4x - 3 + 2x
6 = 6x - 3
6 + 3 = 6x
9 = 6x
x = 6/9
x = 2/3
i helped you with the first two questions so you can see how you can solve it.
hope this helps, God bless!