The answer would be x = 4 miles.

This is equal to:

When you add a negative number, it turns into subtraction.
First, I would change it to mixed numbers:

Now, you need to change the denominators to make sure they are the same on both fractions. I changed the first fraction's denominator to 4 so they match. You can do this by multiplying the numerator by 2:

Now, you simply subtract:
10-9=1
1/4 is your answer.
I hope this helps :)
Eddie is correct about his prediction. A coin has two sides, one head, one tail, so there is a 50% chance that it will land heads every time Eddie flips the coin. I would tell Eddie that his prediction is reasonable and mathematically correct.
A will be the right answer
We know that the perimeter of a rectangle is twice the length, plus twice the width.
P = 2L + 2W
We also know that the perimeter is 156.
P = 156
Finally, we know that the width is 12 less than the length.
W = L - 12.
The next thing that we do is substitute the information that we have into the original equation:
P = 2L + 2W
156 = 2L + 2(L - 12)
From this point we start to solve
156 = 2L + 2L - 24 <---we multiplied the '2' through the parenthesis
156 + 24 = 2L + 2L - 24 + 24
180 = 2L + 2L <--- getting like terms on same sides
180 = 4L <---combining like terms
180/4 = 4L/4 <--- getting like terms on same sides
45 = L <---now we have a value for L
Now we take the known value for L and substitute it in to our equation for W
W = L - 12
W = 45 - 12
W = 33
So now we have Length = 45 and Width = 33.