一元二次方程的解法自我检测
班级______ 姓名______ 成绩________
1.用适当方法解方程:
(1) x2+2=3x; (2) x2=3x+2;
(3) (x-1)(x+2)=70; (4) (3-x) 2=9-x2;
(5) (y+3) 2-2=0; (6) (3x-2)=2(3-x);
(7) x2+(1-3)x+4+=0; (8) 2(x+1)(x+2)=3x(x+2);
(9) (10)
(11) (12)
(13)
2.解关于x的方程:
参考答案:
2.
当a≠0时,
当a=0,bc≠0时,x=b+c,
当a=b=0或a=c=0时,方程的解不定.
1.(1)x2-3x+2=0,x1=1,x2=2;
23x2=0幻-31明.-3g亚,
2
(3)x2+x-72=0,(x+9)(x-8)=0,x1=-9,x2=8;
(4)x2-3x=0,x1=0,x2=3;
(5)y+3=±V2,y1=-3+V2,y2=-3-√2;
g级-5细
(6)9x2-10x-2=0;x1÷5+4超
9
(7)x=1+3y5±/30-105--1+3V5±5-5)2
2
2
=1+35±5-5),x1=2+V5,x2=-3+25;
2
(8)x1=-2,x2=2;
(9)x1=x2=1;
(10)x1=二4+27
x2
4-27,
3
3
936,r2÷6=6
(11)21=6+6
3
(12)
x1=√7,x2=-√7;
(13)x1=-8,x2=0;
(14)x=3±(-V32-4(3+1D2=3)-3±7-43
2(√3+1)
2(√3+1)
=3±2-32=3±(2-3)
2(√3+1)
2(√3+1)
x1
31-1-2-
2
2(√3+1)
2(√3+1)
(15)x1=V2+1,x2=-3-3V/2