Answer:
A
Step-by-step explanation:
The opposite of 6 IS -6
We are given
Jim's backyard:
Length is

width is

Since, this is rectangle
so, we can find area of rectangle



Area of one sod:
length is

width is

Since, it is rectangle in shape
so,



Number of pieces of sod:
we can use formula
Number of pieces of sod = (area of Jim's backyard)/(area of one sod)

now, we can simplify it
pieces need ..............Answer
Answer:
The step 4 is not what he should have done. But the wrong is step 5, because if he added -2x both sides, it would give the following equation:

and not 
Note that in step 4 he should have added 2x and not -2x to both sides, but we still have the equality. The problem is that step 5 is totally wrong.
I don't know what answer is expected to this question, but I would mark step 5, because this is mathematically wrong.
Solving the equation

Using distribution

Add
both sides


Add 12 both sides

Divide both sides by 5

9+3=12
30+20=50
300+100=400
Then add.
12+50+400=462
<span>So 339+123=462</span>