已知A已知A
已知A3B=6B=2A=2-x,C=2-xB^4=A^2*C^22^4=(2-x)^2*(2+x)^2(4-x^2)^2=164-x^2=4or-4x^2=8x=2根号2A=2-2根号2B=2C=2+2根号2