I really need help

A which is x=-3

Step-by-step explanation:

You put 2x to the left hand side which makes it a negative. Then you move the 5 to the other side since 2x has a variable and 5 doesn't. You need to put one side of the equation with a variable and one not. Then 5 becomes -5 because you move it over. So it will be 6x-2x= - 7- 5.Then subtract 6x and 2x which is 4x. -7 subtract -5 equals -12. Divide -12 and 4 which makes it -x=3.

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation:

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