how to solve this equation 3x+12y=25 and 3x+7y=10

Question

Solve the following system of equations.

Answer 1

(1)    3x + 12y = 25        

(2)    3x + 7y = 10

 

Subtract 12y from both sides of equation (1):

(1)  3x = 25 - 12y

You can then substitute this equation into equation (2):

      (25 - 12y) + 7y = 10

      25 - 5y = 10

      -5y = -15

       y = (-15)/(-5)

      y = 3                      

You can then put this value into equation (1) to find the solution of x:

      3x + (12 x 3) = 25

      3x + 36 = 25

      3x = -11

      x = -11/3

 

 

So the solution of the equation is (-11/3, 3)