how to solve 47x+31y=63 31x+47y=15 short trick

Asked by kuldeepsingh89799 | 31st May, 2021, 04:31: PM

Expert Answer:

Given equations are 
 
47 x + 31 y = 63  ....................... (1)

31 x + 47 y = 15 .........................(2)
 
Add and subtract the above equations to get numbers of small magnitudes.
 
By adding (1) and (2) , we get  , 78 x + 78 y = 78  or x + y = 1  ...........................(3)
 
By subtracing eqn.(2) from eqn.(1) , we get ,  16 x - 16 y = 48  or  ( x - y ) = 3  ............(4)
 
Hence by solving eqn.(3) and eqn.(4) , we get , x = 2 , y = -1 

Answered by Thiyagarajan K | 20th Sep, 2021, 02:18: PM