Question

The linear combination method is applied to a system of equations as shown.

4(.25x + .5y = 3.75) → x + 2y = 15
One-fourth(4x – 8y = 12) → x – 2y = 3
2x = 18
What is the solution of the system of equations?

(1,2)
(3,9)
(5,5)
(9,3)

Answer 1

Add the two resulting equations: x + 2y = 15 and x − 2y = 3.
Adding gives 2x = 18, so x = 9. Substitute into x − 2y = 3:
9 − 2y = 3 → −2y = −6 → y = 3.

Solution: (9, 3).