16. A pair of linear equations which has a unique solution x = 2, y = -3 is

(a) x + y = -1; 2x – 3y = -5
(b) 2x + 5y = -11; 4x + 10y = -22
(c) 2x – y = 1; 3x + 2y = 0
(d) x – 4y – 14 = 0; 5x – y – 13 = 0
Answer: (b) 2x + 5y = -11; 4x + 10y = -22
Explanation:
If x = 2, y = -3 is a unique solution of any pair of equations, then these values must satisfy that pair of equations.
By verifying the options, option (b) satisfies the given values.
LHS = 2x + 5y = 2(2) + 5(- 3) = 4 – 15 = -11 = RHS
LHS = 4x + 10y = 4(2) + 10(- 3)= 8 – 30 = -22 = RHS