Problem: In the equation (x−1)(m−1)x(x−1)−(m+1)=mx the roots are equal when
Answer Choices:
A. m=1
B. m=21
C. m=0
D. m=−1
E. m=−21
Solution:
After simplification, we have x2−x−m(m+1)=0. For equal roots the discriminant D=1+4m(m+1)=0=(2m+1)2.
∴m=−21.