Let A= set of values of x for which x2+(m-1)x-2(m+1)=0,x∈R , B= set of values of x for which (m-1)x2+mx+1=0,x∈R. Number of values of m such that A∪B has exactly 3 distinct elements is:

x2+m−1x−2m+1=0⇒x=2  or   x=−m+1m−1x2+mx+1=0⇒x=−1   or  x=−1m−1Case (i) −m+1=−1m−1⇒m=±2Case (ii) −m+1=2⇒m=−3Case (iii) −m+1=−1⇒m=0Case (iv)   −1m−1=−1⇒m=2             Case (v) −1m−1=2⇒m=12