Math

How to Solve Certain Equations with Variables

1. 3.21 + 0.3n = 0.2n + 1.4          

        -0.2n             -0.2n

    3.21 + 0.1n = 1.4

    -3.21              -3.21

    0.1n = -1.8

    0.1n / 0.1 = -1.8 / 0.1

          n = -18

   1.First, we need to get the variable on one side of the equal sign. To do this, we subtract 0.2n from both sides to cancel out the variable on the right. 

    2.That means that we now have 3.21 + 0.1n = 1.4. So now we have to subtract 3.21 from each side to help get the variable alone. That leaves us with 0.1n = -1.8.

    3. Now we divide each side by 0.1 to get the variable totally alone. The answer is n = -18

   

 

    2. 12n = n + 14 + n

        -2n         -2n

         10n = 14

       10n / 10 = 14 / 10

          n = 1.4

      1. First, we subtract 2n from each side because n + 14 + n is basically 2n + 14, and we need to get rid of the variable on that side. So now we have 10n = 14.

      2. Now we divide both sides by ten to get the variable alone with the answer. The answer is: n = 1.4

 

 

     3. (3/4)n + 1.5 = 2.7

             -1.5       -1.5

              .75n = 1.2

        .75n / .75 = 1.2 / .75

           n = 1.6 (or 1 3/5)

       1. First, we subtract 1.5 from each side and get .75n = 1.2 (I changed it to a decimal to make the subtraction easier).

       2. Now we divide each side by .75 to get the variable and the answer alone. The answer is: n = 1.6.

 

 

      4. n/4 - 6 = -8

            +6     +6

          n/4 = -2

         n/4 * 4 = -2 * 4

             n = -8

        1. First, we cancel out the negative 6 by adding six to both sides. Then we get n/4 =  -2.

        2. Then we multiply each side by four to cancel out the division and isolate the variable and answer. The answer is: n = -8

Check: Always check any of your answers with variables by plugging in your answer to the beginning to the equation and solving it to see if it works out before turning it in!!!