Solve the system with the addition method:

Question

Solve the system with the addition method:

 

(7 x -4 y, =, 5)

(21 x -12 y, =, 15)

Answer 1

7x-4y = 5......(1)

21x-12y = 15......(2)

Since dividing each term of the equation (2) by 3 gives you the equation (1), you actually have only one equation with two variables. Therefore, the solution is

{t, (1/4)(7t-5)}, where t can be any number.