如果正比例函數(shù)的圖象經(jīng)過點(-3,5),那么它也經(jīng)過點( )
A.(4,-6)
B.(5,-8)
C.(6,-10)
D.(7,-12)
【答案】
分析:設(shè)出函數(shù)解析式為y=kx,將點(-3,5)帶、代入解析式,求出k的值,再將A、B、C、D分別代入解析式,成立者即為正確答案.
解答:解:設(shè)函數(shù)解析式為y=kx,將點(-3,5)代入解析式得,
k=-
![](http://thumb.zyjl.cn/pic6/res/czsx/web/STSource/20131101190404857805385/SYS201311011904048578053013_DA/0.png)
,則函數(shù)解析式為y=-
![](http://thumb.zyjl.cn/pic6/res/czsx/web/STSource/20131101190404857805385/SYS201311011904048578053013_DA/1.png)
x,
將A、B、C、D分別代入解析式,
A、-6≠-
![](http://thumb.zyjl.cn/pic6/res/czsx/web/STSource/20131101190404857805385/SYS201311011904048578053013_DA/2.png)
×4,故本選項錯誤;
B、-8≠-
![](http://thumb.zyjl.cn/pic6/res/czsx/web/STSource/20131101190404857805385/SYS201311011904048578053013_DA/3.png)
×4,故本選項錯誤;
C、-10=-
![](http://thumb.zyjl.cn/pic6/res/czsx/web/STSource/20131101190404857805385/SYS201311011904048578053013_DA/4.png)
×6,故本選項正確;
D、-12≠-
![](http://thumb.zyjl.cn/pic6/res/czsx/web/STSource/20131101190404857805385/SYS201311011904048578053013_DA/5.png)
×7,故本選項錯誤.
故選C.
點評:本題考查了一次函數(shù)圖象上點的坐標(biāo)特征,求出函數(shù)解析式,將各點代入驗證是解題的關(guān)鍵.