Evaluate this expression: 3x + 9x -5

12x - 5

Step-by-step explanation:

3x + 9x - 5 can be easily simplified by combining like terms.

3x and 9x are like terms because they both contain the same variable and the same exponent (understood to be 1).

Therefore, because an addition sign separates the two terms, it is expected of you to add the two together. To do this, just add the terms together as you would any other terms.

3x + 9x = 12x

Because the 5 is the only constant in the equation, it cannot be combined with anything else.

The simplified expression is 12x - 5.

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