using linear combination method, solve the systems of equations. 3x-4y=14 & 4x+10y=11

Question

Algebra 2

Honors

Answer 1

3x-4y=14          (equation 1)

4x+10y=11.       (equation 2)

 

15x-20y=70        (Multiply first equation by 5)

 8x+20y=22         (Multiply second equation by 2)

 

23x  = 92         (Add equation 1 and equation 2)

   x = 4

3(4) - 4y = 14    (Solve for y)

         -4y = 2

             y = -0.5

 

 

Answer 2

3x-4y=14

4x+10y=11

multiply eq1 by 4 and multiply eq2 by 3

12x-16y=56

12x+30y=33

subtract

     -46y=23

          y=-23/46

          y=-1/2

substitute into original eq1 or eq2

4x-5=11

4x=16

x=4

(4,-1/2) is the solution