3x2+x−1=4|x2−1| Case 1: If x∈[−1,1], 3x2+x−1=−4x2+4 ⇒7x2+x−5=0‌‌∵D=141>0 ∴ Equation has two roots Case 2: If x∈(−∞,−1]∪[1,∞) 3x2+x−1=4x2−4 ⇒x2−x−3=0 ∵‌‌D=13>0 ∴ Equation has two roots So, total 4 roots.