It would be the negative form of those bumbers and the non-negative form of those numbers. The absolute value applies to negative numbers the same. For example absolute value of -3 is 3.
12 x 2 = 24 (Julio), 24 x 4 = 96 (David).
Yes it is the same. 1/4 +1/4 = 1/2. so 9/10-1/2=9/10-1/2
Answer: This coil will not be enough to complete the job.
Step-by-step explanation:
The circumference of the coil of wiring can be calculated with:

Where r is the radius and 
The radius can be calculated by dividing the diameter by 2. Then:

Convert 9 inches to yards (1 yard=36 inches):

Substitute this radius into the formula:

Since there are 21 circles of wire, you need to multiply
by 21:

The coil has 32.97 yards of wire and Alex needs 34 yards, therefore, this coil will not be enough to complete the job.