Question

Solve the system of equations.
3x+6y=21
3
𝑥
+
6
𝑦
=
21

–5x+2y=13

Answer 1

Solve for x from the first equation: divide by 3 -> x + 2y = 7, so x = 7 − 2y.
Substitute into the second: −5(7 − 2y) + 2y = 13 → −35 + 10y + 2y = 13 → 12y = 48 → y = 4.
Then x = 7 − 2·4 = −1.

Solution: (x, y) = (−1, 4).