9（x²-1）²-4（x²+1）²=0【3（x²-1）-2（x²+1）】【3（x²-1）+2（x²+1）】=0（x²-5）（5x²-1）=0x²-5=0,5x²-1=0x1=√5,x2=-√5,x3=√5/5,z4=-√5/5...