Subtract second from third: (9a + 3b + c) − (4a + 2b + c) = 2.5 − 1.8 → 5a + b = 0.7 - AMAZONAWS

Subtract Second from Third: Simplify (9a + 3b + c) − (4a + 2b + c) = 5.2 − 1.5 and Solve for a and b