solve the system of equations

Question

3a-12b=-6

6a+40c=32

24b+30c=38

Answer 1

3a -12b = -6

6a + 40c = 32                                                 Test:

24b +30c = 38                                                    

                                                                     3(4/3) - 12(5/6)= 4 - 10 = -6

                                                                     6( 4/3) + 40 (3/5) = 8+24 =32

Multiply first by -2 , and add to 2nd.                  24(5/6) + 30( 3/5) = 20+18= 38

                                                                     

  -2 ( 3a -12b ) = -6

        6a +40c  = 32

        24b +40c = 44

       -(24b +30c  =38)

                 10c  = 6

 

          c = 3/5

     Substitute in 2nd equation:

     6a + 40(3/5) = 32

 

     6a = 32 -24 = 8

        a = 4/3

     Substitute in

      first equation

 

    3(4/3) - 12b = -6

      -12b = -10

 

       b =5/6