解以下一元二次不等式:
问题描述:
解以下一元二次不等式:
1.x²+4x-12≥0
2.x²+8x+16≥0
3.2x²-2x-7≥0
4.-2x²-4x+6≤0
答
1.x²+4x-12≥0(x-2)*(x+6)≥0∴ x=22.x²+8x+16≥0(x+4)^2≥0∴ x∈R32x²-2x-7≥0由2x²-2x-7=0 得x=(1+√15)/2 或 =(1-√15)/2 ∴ x=(1-√15)/2 4.-2x²-4x+6≤0 x²+2x-3≥0(x-1)*(x+...