5c+5d+8c+4d or the simplified version is 13c+9d
8 * 10^3 is larger than 4 * 10^2
10*10*10 = 1000 * 8 = 8000
10*10= 100 * 4 = 400
5/x = -9
5 = -9x (we have multiplied x out from the denominator)
5/-9 = x (divided by -9 to isolate x)
350/20 = unit rate
350/20 = 17.5 or 17 and 1/2
17.5 miles per one gallon
875/17.5 = 50 gallons
Answer: 50 gallons of gas