When looking at a graph, how do you determine whether it is positive or negative?

You have 6 dollars +12 pennies +to quarters + 4 dimes=2 nickels how much do you have

Which shows the correct substitution of the values a,b and c from the equation 1=-2x+3x^2+1

Cal's go cart has a gas tank with the dimensions shown below. he uses a gas can that holds 11 gallon of gas, to fill the go cart tank. 11 gallon = 231 inches^3 how many full gas cans will it take to fill the go cart's gas tank?