问题
解答题
计算与解方程: (1)
(2)
(3)
(4)3x(x-1)=x-1 (5)x2+4x+3=0 (6)2x2-x-2=0. |
答案
(1)原式=3
-32
+22
=2;
(2)原式=3a2÷
×9a 2 a 6
=
a;1 3
(3)原式=
+1+33
-1+3
-3×1 4 3 3
=3
+3
;1 4
(4)方程整理得:3x(x-1)-(x-1)=0,
分解因式得:(3x-1)(x-1)=0,
可得3x-1=0或x-1=0,
解得:x1=
,x2=1;1 3
(5)分解因式得:(x+1)(x+3)=0,
可得x+1=0或x+3=0,
解得:x1=-1,x2=-3;
(6)这里a=2,b=-1,c=-2,
∵△=1+16=17,
∴x=
,1± 17 4
则x1=
,x2=1+ 17 4
.1- 17 4