Answer:
let the numbers be xy
general form of the number =10x+y
sum of digits of a number =14
x+y=14………[1]
if 18 is added to the number, then digits are interchanged
10x+y+18=10y +x
9x-9y=-18
X-y=-2………[2]
the linear equations are 1) x+y=14
2) X-y=-2
adding [1],[2]
2x=12
x=6
x+y=14
y=14-x
y=14-6
y=8
there fore the number =10*6+8
=68
check:-
1)6+8=14
2)68+18=86
I hope this helped!
Explanation: