Question

Find the unique solution of the pair of linear equations x + 2y = 5, 7x + 3y = 13.

Answer 1

x + 2y = 5------(i)

7x + 3y = 13----(ii)

(i) $\times$ 3 $\to$ 3x+ 6y = 15 -------(iii)
(ii) $\times$ 2 $\to$ 14x + 6y = 26------(iv)

(iv) - (iii) $\to$ 11x = 11 $\to$ x = 1.

Substitute the value of x in (i), we get y = 2.

(x, y) =(1, 2)