题目内容
6.方程组$\left\{\begin{array}{l}{(x-y)(x+2y-1)=0}\\{(x+y-2)(x+y-1)=0}\end{array}\right.$ 可以转化为二元一次方程组$\left\{\begin{array}{l}{x-y=0}\\{x+y-2=0}\end{array}\right.$,$\left\{\begin{array}{l}{x-y=0}\\{x+y-1=0}\end{array}\right.$,$\left\{\begin{array}{l}{x+2y-1=0}\\{x+y-2=0}\end{array}\right.$和$\left\{\begin{array}{l}{x+2y-1=0}\\{x+y-1=0}\end{array}\right.$.分析 解原方程组中①得出x-y=0或x+2y-1=0;解原方程组中②得出x+y-2=0或x+y-1=0.方程①和②的解中各取一个结论联立成方程组即可得出结论.
解答 解:$\left\{\begin{array}{l}{(x-y)(x+2y-1)=0①}\\{(x+y-2)(x+y-1)=0②}\end{array}\right.$.
由①可得:x-y=0或x+2y-1=0;
由②可得:x+y-2=0或x+y-1=0.
∴方程组$\left\{\begin{array}{l}{(x-y)(x+2y-1)=0}\\{(x+y-2)(x+y-1)=0}\end{array}\right.$ 可以转化为二元一次方程组有$\left\{\begin{array}{l}{x-y=0}\\{x+y-2=0}\end{array}\right.$,$\left\{\begin{array}{l}{x-y=0}\\{x+y-1=0}\end{array}\right.$,$\left\{\begin{array}{l}{x+2y-1=0}\\{x+y-2=0}\end{array}\right.$和$\left\{\begin{array}{l}{x+2y-1=0}\\{x+y-1=0}\end{array}\right.$.
故答案为:$\left\{\begin{array}{l}{x-y=0}\\{x+y-2=0}\end{array}\right.$,$\left\{\begin{array}{l}{x-y=0}\\{x+y-1=0}\end{array}\right.$,$\left\{\begin{array}{l}{x+2y-1=0}\\{x+y-2=0}\end{array}\right.$和$\left\{\begin{array}{l}{x+2y-1=0}\\{x+y-1=0}\end{array}\right.$.
点评 本题考查了高次方程,将高次方程组转出成二元一次方程组是解题的关键.
(1)所有的等边三角形都全等
(2)两个三角形全等,它们的最大边是对应边
(3)两个三角形全等,它们的对应角相等
(4)对应角相等的三角形是全等三角形.
| A. | 1 | B. | 2 | C. | 3 | D. | 4 |
| A. | (20%+x)人 | B. | 20%x人 | C. | (1+20%)x人 | D. | $\frac{x}{1+20%}$人 |
| A. | 一,二,三象限 | B. | 一,二,四象限 | C. | 一,三,四象限 | D. | 二,三,四象限 |