-6x-8y=-4 x+y=1 solve by subsitition

Question

solve by subsition

Answer 1

I would solve for one of the variables in one equation and then plug that value into the second equation . . .

-6x - 8y = -4  solve for x

-6x = 8y - 4  divide both sides by -6

x = -8/6y + 4/6  reduce fractions as possible

x = -4/3 y + 2/3

 

x + y = 1

-4/3 y + 2/3 +y = 1  combine y terms

-1/3 y +2/3 = 1  collect number values

-1/3y = 1/3  multiple both sides by -3

y = -1

 

substitute y = -1 into the equation to find x

 

x+ y = 1

x + -1 = 1

x = 2

Answer 2

 - 6X - 8y = -4

 

   X + Y = 1

 

   Solving X from 2nd equation

 

   X = 1 - Y

 

  Substituting back X in the 1st equation

 

  - 6 ( 1 - Y) - 8Y = - 4

 

   - 6 + 6 y - 8 Y = -4

 

      - 2 Y = 2

 

        Y = -1

 

    Substitute  Y back into first equation:

 

       -6X - 8( -1)= -4

    

        - 6X = -12

 

           X = 2