If 3x+y+2x−y=2 and 9x+y−4x−y=1 then
(a) x=12,y=32 (b) x=52,y=12 (c)x=32,y=12 (d) x=12,y=52
3x+y+2x−y=29x+y−4x−y=1Put 1x+y=u and 1x−y=v3u+2v=2−−−(1)9u−4v=1−−−(2)(1)×39u+6v=6−−−(3)(3)−(2)10v=5v=510=123u+2v=23u=2−2u2−2×12=2−1=13u=1u=131x+y=u=13x+y=31x−y=v=12x−y=22x=5x=52y=3−52=6−52=12 x=52 and y=12