1.X²+Y²=50.
(X-Y)²=60 X²+Y²-2xy=60 50-2xy=60 xy=-5
(X+Y)²= X²+Y²+2xy=50-10=40
X+Y=±√40=±2√10
2.X+Y=6,XY=5,
X²+Y²=(.X+Y)²-2xy=6²-2×5=26
(X-Y)²=(.X+Y)²-4xy=6²-4×5=16
X-Y=±√16=±4
3.X+Y=-1,
X²+Y²=25,(X+Y)²-2xy=25 (-1)²-2xy=25 xy=-12
(X-Y)²=(X+Y)²-4xy=(-1)²-4×(-12)=49
X-Y=±√49 =±7
4.X-Y=1.,XY=6,
X²+Y²=(.X-Y)²+2xy=1²+2×6=13
(X+Y)²=(.X-Y)²+4xy=1²+4×6=25
X+Y=±√25=±5