The sides of a triangle ABC satisfy the relations a+b-c=2 and 2ab-c2=4. then square of the area of triangle is
1
2
3
4
a+b-c=2----1
and 2ab-c2=4-----2
⇒a2+b2+c2+2ab-2bc-2ca=4=2ab-c2
⇒b-c2+a-c2=0
⇒a=b=c
triangle is equilateral
⇒a=2
⇒∆=3