Answer:
13.8 miles a gallon
Step-by-step explanation:
I think this because 345 divided by 25 equals 13.8 which would mean 13.8 miles for every gallon
Ten thousand is the place value of the 9 in that number
You put all the numbers on one side of the equation and letters on another.
0.25r + 0.5r - r = 0.5 +0.125
-0.75r = 0.625 divide both sides by -0.75
r = -0.125
in rectangular form the equation is 
