跟你商量一下,把原题等号右边改成5-2X^2-X^3-6X=5X(X^2+2X+6)= -5X[(X+1)^2+5]+5=0X(X+1)^2+5x+5=0X(X+1)^2+5(x+1)=0(X+1)[X(X+1)+5]=0(X+1)[(X+1/2)^2+19/4]=0(X+1/2)^2+19/4=0 无解,所以 X+1=0,X= -1嘿嘿...