Answer:
B: $2.50
Step-by-step explanation:
Step 1: form an equation
126 = 12(8 + x)
Step 2: isolate the x
126/12 = 8 + x
126/12 - 8 = x
Step 3: solve
10.5 - 8 = x
2.5 = x = raise per hour
Greetings!
An item at full price is 100%, or by using the percentage formula: 
If something is at 30% off, that means it is 70% of the original price (because minus the percentage from the 100%)
So by substituting the numbers into the percentage formula you end up with:
which is 0.7
So your answer would be D, 0.7!
Hope this helps!
The answer is D. I graphed it on this website called desmos. The solution is where the lines intersect.