Solve :217x +131y=913

131x+217y=827

217x+131y=913
131x+217y=827
Fristly add up both eqn.
217x+131y=913
+
131x+217y=827
_____________

348x+348y=1740

Dividing both side by 348

We get x+y=5---1

Similarly Subtract given eqn

217x+131y=913
-
131x+217y=827
____________
86x-86y = 86
Dividing both side by 86 We get
x-y =1------2eqn
Now solve eqn 1&2

x+y=5
+
x-y=1
_____
2x=6
x=3
Put x=3 in eqn 1
x+y=5
3+y=5
y =5-3
y=2
Hence x=3 y=2