解几个初二填空题如图~1-4

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解几个初二填空题如图~1-4

解几个初二填空题如图~1-4
解几个初二填空题如图~1-4

解几个初二填空题如图~1-4
1, C
2 x=[-b±√(b²-4ac)]/2a
3 a=1 b=-4 c=3 b²-4ac=16-12=4 方程的根为-1和-3
4 ∵a=1 b=2√2 c=-5
∴b²-4ac=8+20=28
∴x=[(-2√2)±2√7]/2
∴x1=-√2-√7 x2=-√2+√7

如图: Mr smith has visited China twice since 1998. Have you written to your father recently? Yes, I did. What is Tom doing now? He

推荐答案的第三题错了如下
1. C
2. x=[-b±√(b²-4ac)]/2a
3. a=1 b=-4 c=3 b²-4ac=16-12=4 方程的根为1和3
4. ∵a=1 b=2√2 c=-5
∴b²-4ac=8+20=28
∴x=[(-2√2)±2√7]/2
∴x1=-√2-√7 x2=-√2+√7