更新時(shí)間:2024-01-12 16:28:49作者:貝語(yǔ)網(wǎng)校
作出函數(shù)y=-2x+3的圖象,觀察圖象并回答下列問(wèn)題
(1)x取何值時(shí),-2x+3>0;
(2)x取何值時(shí),-2x+3=0;
(3)x取何值時(shí),-2x+3<0.
解:當(dāng)x=0時(shí),y=3;
當(dāng)y=0時(shí),x=.
即函數(shù)y=-2x+3的圖象經(jīng)過(guò)點(diǎn)(0,3),(,0),其圖象如圖:
(1)由圖象可知,x<時(shí),-2x+3>0;
(2)由圖象可知,x=時(shí),-2x+3=0;
(3)由圖象可知,x>時(shí),-2x+3<0.
先根據(jù)一次函數(shù)式y(tǒng)=-2x+3作出該函數(shù)圖象,然后根據(jù)圖象來(lái)回答問(wèn)題.
點(diǎn)評(píng):本題主要考查了一次函數(shù)的圖象與性質(zhì).此類題可用數(shù)形結(jié)合的思想進(jìn)行解答,這也是速解習(xí)題常用的方法.