设集合A={x│-2
问题描述:
设集合A={x│-2
答
2m²-m-1=(2m+1)(m-1)
x^2-3mx +2m²-m-1 = x^2-3mx +(2m+1)(m-1)= (x-(2m+1))(x-(m-1))-2
则-2 -1 切m-2得到-1