Answer:
x = 2, y = -1
Explanation:
47x + 31y = 63...eqn 1
31x + 47y = 15...eqn 2
multiply eqn 1 by 47 to get eqn 3 and multiply eqn 2 by 31 to get eqn 4...
=> 2209x + 1457y = 2961...eqn 3
=> 961x + 1457y = 465...eqn 4
subtract eqn 4 from eqn 3
=> 1248x = 2496
=> x =2
subst x =2 in eqn 1
=> 94 + 31y = 63
=> 31y = -31
=> y = -1