My car gets 23 miles per gallon at 60 miles per hour. Is the number of miles I can drive at 60 miles per hour a linear function of the number of gallons of gas in the tank? Explain your reasoning.

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  yes

Step-by-step explanation:

The constant ratio (23 mi)/(1 gal) tells you the number of miles is a linear function of the number of gallons.

  miles = (miles/gallon) × gallons

  miles = constant × gallons . . . . . a linear function of gallons

on your paper it doesn't say the answer but the the answer is altitude

step-by-step explanation:

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18