Question

Solve the system of linear equations x + 2y = 3, 7x - 15y = 2.

Answer 1

From x + 2y = 3, x = 3 − 2y. Substitute into 7x − 15y = 2:

7(3 − 2y) − 15y = 2
21 − 14y − 15y = 2
21 − 29y = 2
−29y = −19 ⇒ y = 19/29.

Then x = 3 − 2(19/29) = 87/29 − 38/29 = 49/29.

Solution: x = 49/29, y = 19/29.