Question

3x-4y= 20, 3x+ 2y =8
solve by substitution and elimination method​

Answer 1

Answer:

by substitution method:

3x-4y= 20------------(1)

3x+ 2y =8---------------(2)

3x = 20+4y

putting value of 3x in eq(2)

20+4y+2y=8

20  +  6y   = 8

        6y    =  8-20

            6y  = -12

            y = -12/6 = -2

             3x= 20+4y

              3x= 20+4 . -2

               x = 12/3

               x = 4

by elimination method

subtracting eq (2) from equation(1)

(3x-4y) - (3x+ 2y )= 20- 8

3x-4y - 3x-2y    = 12

         - 6 y   = 12

             y = 12/-6

            y   = -2

substituting value of y  in eq(2)

3x+2y  = 8

3x + 2(-2)  = 8

 3x - 4     = 8

      3x =   8+4

           x = 4