What is the value of 13x^-3 for x= -1 and y= 4?

  -13

Step-by-step explanation:

Put the value of x where x is in the expression and do the arithmetic.

  13(-1)^-3 = 13/(-1)^3 = 13/-1 = -13

use an equation of ratios to determine the amount of gas needed to fill the tank.

    0.2             0.8

  =    

288.75             x

                                                              231 gal

so, 0.2x = (0.8)(288.75 gal), and x = = 1155 gal.

                                                                0.2

it would take 1155 gal. to fill the tank.

the cost would be

1155 gal         $3

* = $3465   (answer)

      1           1 gal

hope this you