Math Chapter Wise Theory Of Equation And Inequations English MCQ UP PCS (Pre) 1997, PGT 2013 Q.The equation f(x)=x3 –x2 –8x+12=0 has double root α, then α is a root of: Af"(x) = 0 Bf'(x)=0 Cf(x)+f"(x)=0 Dfx(x)+10=0 Show answer Correct answer: f'(x)=0