It costs $57.19 to fill up a 19 gallon gas tank and $54.18 to fill up an 18 gallon tank.

What is the constant of proportionality that relates the cost in dollars,
y, to the number of gallons of gas, x?

y=3.01x

Step-by-step explanation:

We can see that since 19 gallons cost $57.19 and 18 gallons cost $53.18, 1 gallon (19-18) must cost $3.01.

Therefore, y=3.01x

You can check this with algebra

1.3

step-by-step explanation:

3x2=6   9x+6

bring down the 6 on both sides

6+6=12

12= 9x

divide by 9

12/9 =

1.3 =x

the 8 in 8,420 is in the thousands place so it's value is 8 thousand.

the 8 in 6,870 is in the hundreds place so it's value is 8 hundred.

divide 8000 by 800 to find the answer:

8000 / 800 = 10

the 8 in 8,420 is 10 times greater than the 8 in 6,870