Question 90772



     SOLVE THE SYSTEM BY ADDING OR SUBTITUTION
3X+6y=0
x=2/3 
solve the sysem by adding
5x-4y+-12
x+5y=15


    1) x = 2/3.......(1)

       3x+6y = 0.....(2)

       substitute for x in (2)

                3*2/3+6y = 0

                     6y = -2   or y = -1/3

             The solution is (2/3, -1/3)



     2)5x-4y = 12.......(1)

        x+5y = 15.......(2)

        multiply (2) by -5  and add to (1)

            -5x-25y = -75

             5x-4y =   12

                -29y = -63
                  y = 63/29

      To find x substitute for y in (2)

         x = 15-5y = 15-5(63/29) =( 435-315)/29 = 120/29

      The solution is (120/29,63/29)