Question

if 15x+17y=31 &17x+15y=21,find the value of(x-y)​

Answer 1

Answer:

The value of (x-y) is -5.​

Step-by-step explanation:

             $15x+17y=31----(1)\\ \\ 17x+15y=21----(2)$

Equation (1) is subtracted from equation (2), We get

             $(17x+15y)-(15x+17y)=21-31\\ \\ 17x+15y-15x-17y=21-31\\ \\ 17x-15x+15y-17y=21-31\\ \\ 2x-2y=-10\\ \\ 2(x-y)=-10\\ \\ x-y=\frac{-10}{2} =-5$