,我的步骤很详细3a2-a-2=0(3a+2)(a-1)=0若3a+2=0,a-1不等于0时,a=-2/3若a-1=0,3a+2=0不等于0时,a=1当a=-2/3时,则5+2a-6a²=5+2（-2/3）-6（-2/3）a²=3当a=1时,则5+2a-6a²=5+2x1-6x1²=1那个答案肯...