The calculation is not reasonable, because 0.45 is less tha 1/2 ( 0.50) and what he has for an answer is half the distance ( 250.17 is 1/2 of 500.34).
To find actual mileage, multiply by 0.45:
500.34 x 0.45 = 225.153 miles.
Round the answer as needed.
Isolate the x. Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS (Parenthesis, Exponents (& roots), Multiplication, Division, Addition, Subtraction)
First, subtract 6 from both sides
-4x + 6 (-6) = -38 (-6)
-4x = -38 - 6
-4x = -44
Next, fully isolate the x by dividing -4 from both sides
(-4x)/-4 = (-44)/-4
x = -44/-4
x = 11
11 is your answer for x.
~
3x+5=0
3x=0-5
3x=-5
Divide both sides by 3
-1.6666.......
Hope it helps.
As for mod 9, I don't understand.