9- 12n 2 + 4n 3 - 7n 1) 4n3 - 12n2 - 7n + 9 2) -4n3 + 12n2 + 7n - 9 3) 4n3 + 12n2 + 7n + 9 4) -4n3 - 12n2 + 7n - 9

b.) 160 miles on a 5 gallons car

step-by-step explanation:

240/10=24 miles/gallon

160/5=32 miles/gallon

30/1=30 miles/gallon

168/6= 28 miles/gallon

32 miles/gallon is the most amount, so this is the best.

ruth is 6 years old

step-by-step explanation:

6 + 24 = 30,   so 6/30 = .2  

if you do 1/5 it also equals .2, so that is the answer.