Allen's work is not written properly so I have rearranged it as shown below:
Original problem) –8.3 + 9.2 – 4.4 + 3.7.
Step 1) −8.3 + 9.2 + 4.4 + 3.7 Additive inverse
Step 2) −8.3 + 4.4 + 9.2 + 3.7 Commutative property
Step 3) −8.3 + (4.4 + 9.2 + 3.7) Associative property
Step 4) −8.3 + 17.3
We can see that in step 1), Allen changed -4.4 into +4.4 using additive inverse. Notice that we are simplifying not eliminating -4.4 as we do in solving some equation. Hence using additive inverse is the wrong step.
Alen should have collect negative numbers together and positive numbers together.
Add the respective numbers then proceed to get the answer.
–8.3 + 9.2 – 4.4 + 3.7
= –8.3 – 4.4 + 9.2 + 3.7
= -12.7 + 12.9
= 0.2
Answer:
Step-by-step explanation:
Given
Restrained Force 
Increase in Kinetic Energy 
Distance moved d=1.9 m
Work done by all the forces is equal to change in Kinetic Energy of Object i.e. by gravity force, Normal force and Applied Force




(b)In absence of applied force thus
work done by gravity will be equal to change in kinetic Energy
change in Kinetic Energy
V=w•h•l
w=2 1/2=5/2=2.5 m
h=1 3/4=7/4=1.75 m
l= 2 1/4=9/4=2.25 m
V= 2.5 •1.75 •2.25
V=9.84 m^3