Answer:
x+2y= -10......eqn(i)
3x-y=12.........eqn(ii)
multiply the eqn(ii) by 2
x+2y= -10
6x-y=12
or, 7x=14
or, x=14/7
or, x=2
now, substituting the value of x=2 in eqn(i)
x+2y= -10
or, 2+2y= -10
or, 2y= -10-2
or, 2y= -12
or, y= -12/2
or, y= -6
therefore the equation is proved
