方程有实根,判别式△≥0[2(1+a)]²-4(3a²+4ab+4b²+2)≥0-2a²+2a-4ab-4b²-1≥02a²-2a+4ab+4b²+1≤0a²-2a+1+a²+4ab+4b²≤0(a-1)²+(a+2b)²≤0平方项恒非负...