數(shù)學(xué)八上人教版第15章一次函數(shù)練習(xí)

一次函數(shù)練習(xí)/r/n南通市八一中學(xué)葛水芳/r/n1．/r/n駱駝被稱為/r/n“/r/n沙漠之舟/r/n”/r/n，它的體溫隨時間的變化而變化，在這一問題中，自變量是/r/n/r/nA.沙漠B.體溫C.時間D.駱駝/r/n/r/n（/r/n/r/n）/r/n2．下面兩個變量是成正比例變化的是/r/n/r/n（/r/n/r/n）/r/nA．正方形的面積和它的邊長．B．變量/r/nx/r/n增加,變量/r/ny/r/n也隨之增加;/r/nC．矩形的一組對邊的邊長固定,它的周長和另一組對邊的邊長．/r/nD．圓的周長與它的半徑．/r/n3．下面哪個點不在函數(shù)/r/ny=/r/n－/r/n2x+3/r/n的圖象上/r/n/r/n（/r/n/r/n）/r/nA/r/n．（/r/n-5/r/n，/r/n13/r/n）/r/n/r/n/r/nB/r/n．（/r/n0.5/r/n，/r/n2/r/n）/r/nC/r/n．（/r/n3/r/n，/r/n0/r/n）/r/n/r/n/r/nD/r/n．（/r/n1/r/n，/r/n1/r/n）/r/n4/r/n．下列說法中不成立的是/r/n/r/n（/r/n/r/n）/r/nA．在y=3x-1中y+1與x成正比例；B．在y=-/r/n中y與x成正比例/r/nC．在y=2（x+1）中y與x+1成正比例；D．在y=x+3中y與x成正比例/r/n5．已知（/r/nx/r/n1/r/n，y/r/n1/r/n）和（x/r/n2/r/n，y/r/n2/r/n）是直線y=-3x上的兩點，且/r/nx/r/n1/r/n>x/r/n2/r/n，則y/r/n1/r/n與y/r/n2/r/n/r/n的大小關(guān)系是/r/nA．/r/ny/r/n1/r/n>y/r/n2/r/nB．y/r/n1/r/n<y/r/n2/r/nC/r/n．y/r/n1/r/n=y/r/n2/r/n/r/nD．以上都有可能/r/n/r/n（/r/n/r/n5．已知點（-4，/r/ny/r/n1/r/n），（2，/r/ny/r/n2/r/n）都在直線/r/ny=/r/n-/r/nEQ\F(1,2)/r/nx+2/r/n上，則/r/ny/r/n1/r/n/r/n、/r/ny/r/n2/r/n大小關(guān)系是/r/nA/r/n．/r/n/r/ny/r/n1/r/n/r/n>/r/ny/r/n2/r/nB/r/n．/r/n/r/ny/r/n1/r/n/r/n=/r/ny/r/n2/r/nC/r/n．/r/ny/r/n1/r/n/r/n</r/ny/r/n2/r/nD/r/n．/r/n不能比較/r/n/r/n（/r/n/r/n6．/r/n下列函數(shù)中，圖象經(jīng)過原點的為/r/n/r/n/r/n（/r/n/r/n）/r/nA．/r/ny/r/n=5/r/nx/r/n+1/r/n /r/n /r/n B．/r/ny/r/n=-5/r/nx/r/n-1/r/n/r/n/r/nC/r/n．/r/ny/r/n=-/r/n /r/n /r/nD．/r/ny/r/n7/r/n．/r/n已知一/r/n次函數(shù)/r/ny=/r/na/r/nx+4與y/r/n/r/n=/r/n/r/nbx-2的圖象在x軸上相交于同一/r/n點/r/n,則/r/n的值是/r/n/r/n/r/nA．4B．/r/n-2C/r/n．/r/n/r/nEQ\F(1,2)/r/nD．/r/n-/r/n/r/nEQ\F(1,2)/r/n/r/n（/r/n/r/n）/r/n8/r/n．/r/n已知一次函數(shù)y=kx+b,y隨著x的增大而減小,且kb<0,則在直角坐標(biāo)系內(nèi)它的大致圖象是/r/n（/r/n/r/n）/r/nA．/r/n/r/nB．/r/n/r/n/r/nC．/r/n/r/nD/r/n9/r/n．/r/n一水池蓄水/r/n20m/r/n3/r/n，打開閥門后每小時流出/r/n5m/r/n3/r/n，放水后池內(nèi)剩下的水的立方數(shù)/r/nQ/r/n(m/r/n3/r/n)與放水/r/n時間/r/nt/r/n(時)的函數(shù)關(guān)系用圖表示為/r/n/r/n/r/n/r/n（/r/n10/r/n．/r/n已知函數(shù)/r/ny=-x+m/r/n與/r/ny=mx-4/r/n的圖象的交點在/r/nx/r/n軸的負(fù)半軸上那么/r/nm/r/n的值為/r/n/r/n/r/nA/r/n．/r/n±/r/n2/r/n/r/nB/r/n．/r/n±/r/n4/r/n/r/n/r/n/r/nC/r/n．/r/n2/r/n/r/nD/r/n．/r/n-2/r/n11．/r/n下列函數(shù)關(guān)系中表示一次函數(shù)的有/r/n/r/n/r/n（/r/n/r/n）/r/n①/r/n②/r/n③/r/n/r/n④/r/n⑤/r/n/r/nA.1個B.2個C.3個D.4個/r/n12．/r/n如果直線/r/n經(jīng)過一、二、四象限，則有/r/n/r/n/r/n（/r/n/r/n）/r/nA.k>0,b>0/r/nB.k>0,b</r/n0C/r/n.k<0,b>0/r/nD.k<0,b<0/r/n13．/r/n直線/r/n經(jīng)過A(0,2)和B(3,0)兩點,那么這個一次函數(shù)關(guān)系式是/r/n/r/n（/r/n/r/n）/r/n/r/n/r/n(A)/r/n(B)/r/n(C)/r/n(D)/r/n14．/r/n汽車由北京駛往相距120千米的天津，它的平均速度是30千米/時，則汽車距天津的路程S（千米）與行駛時間t（時）的函數(shù)關(guān)系及自變量的取值范圍是/r/n/r/n（/r/n/r/n）/r/n/r/n/r/nA．S=120-30t（0/r/n≤/r/nt/r/n≤/r/n4）B．S=30t（0/r/n≤/r/nt/r/n≤/r/n4）/r/nC．S=120-30t（t>0）D．S=30t（t=4）/r/n15．/r/n已知函數(shù)y=/r/n中，當(dāng)x=a時的函數(shù)值為1，則a的值是/r/n/r/n（/r/n/r/n）/r/nA．-1B．/r/n1C/r/n．-3D．3/r/n16．/r/n星期天晚飯后，小紅從家里出發(fā)去散步，圖描述了她散步過程中離家s（米）與散步所用的時間t(分)之間的函數(shù)關(guān)系．依據(jù)圖象，下面描述符合小紅散步情景的是/r/n/r/n（/r/n/r/n）/r/n/r/nS/r/n（米）/r/nS/r/n（米）/r/n/r/n18/r/n/r/n（分）/r/n/r/n(B)從家出發(fā),一直散步(沒有停留),然后回家了./r/n(C)從家出發(fā),到了一個公共閱報欄,看了一會報后,/r/n繼續(xù)向前走了一會,然后回家了./r/n(D)從家出發(fā),散了一會步,就找同學(xué)去了,18分鐘后/r/n才開始返回./r/n17．/r/n自變量x的取值范圍是/r/n/r/n。/r/n1/r/n8/r/n．/r/n若一次函數(shù)/r/n是正比例函數(shù)，則/r/n的值為/r/n/r/n。/r/n1/r/n9/r/n．一次函數(shù)y=-3x+6的圖象與x軸的交點坐標(biāo)是/r/n/r/n/r/n，與y/r/n軸的交點/r/n坐標(biāo)是/r/n/r/n/r/n。/r/n20/r/n．設(shè)地面（海拔為/r/n0km/r/n）氣溫是/r/n20/r/n0/r/nC/r/n，如果每升高/r/n1km/r/n，氣溫下降/r/n6/r/n0/r/nC/r/n，則某地的氣溫t（/r/n21/r/n．若函數(shù)/r/ny=/r/n-/r/nx/r/n-4與x/r/n軸/r/n交于點A，直線上有一點M，若/r/n△/r/nAOM的/r/n面積為/r/n8/r/n，/r/n則點M的坐標(biāo)/r/n_______/r/n/r/n22．/r/n已知一次函數(shù)y=6-5x中，y隨x的增大而/r/n_____/r/n23．/r/n若直線y=2x+b與兩坐標(biāo)軸圍成的三角形的面積是9，則b=/r/n/r/n./r/n24．/r/n如果一次函數(shù)y=mx+1與y=nx－2的圖象相交于x軸上一點，那么/r/nm/r/n∶/r/nn=/r/n/r/n./r/n25．/r/n寫出同時具備下列兩個條件的一次函數(shù)表達(dá)式（寫出一個即可）/r/n/r/n./r/n（1）/r/ny/r/n隨著/r/nx/r/n的增大而減小。（2）圖象經(jīng)過點（1，-3）/r/n26．/r/n直線y=2x-5與y=-x+1的交點坐標(biāo)是__________/r/n27．/r/n如圖，先觀察圖形，然后填空：（1）當(dāng)x/r/n/r/n時，/r/n＞0；/r/n（2）當(dāng)x/r/n/r/n時，/r/n＜0；/r/n0/r/nS(km)/r/nt(分)/r/n0/r/nS(km)/r/nt(分)/r/n9/r/n30/r/n40/r/n12/r/n16/r/n⑴/r/n汽車在前9分鐘內(nèi)的平均速度是/r/n/r/nkm/分；/r/n⑵/r/n汽車在中途停了多長時間？/r/n/r/n；/r/n⑶/r/n當(dāng)16/r/n≤/r/nt/r/n≤/r/n30時，S與t的函數(shù)關(guān)系式/r/n/r/n29．/r/n根據(jù)下列條件求函數(shù)的解析式/r/n/r/n/r/n①/r/ny與x/r/n2/r/n成正比例，且x=-2時y=12．/r/n/r/n/r/n②/r/n函數(shù)y=（/r/nk/r/n2/r/n-4）/r/nx/r/n2/r/n+（k+1）x是正比例函數(shù)，且y隨x的增大而減?。?r/n30．/r/n已知一次函數(shù)的圖象經(jīng)過點A（-3，2）、B（1，6）．/r/n①/r/n求此函數(shù)的解析式，并畫出圖象．/r/n②/r/n求函數(shù)圖象與坐標(biāo)軸所圍成的三角形面積．/r/n31．/r/n已知函數(shù)y=(/r/n2m/r/n+1)x+m/r/n-/r/n3/r/n(1)若這個函數(shù)的圖象經(jīng)過原點,求m的值/r/n(2)若這個函數(shù)的圖象不經(jīng)過第二象限,求m的取值范圍./r/n32．/r/n已知直線m與直線y=－0.5x+2平行，且與y軸交點的縱坐標(biāo)為8，求直線m的解析式./r/n33．/r/n已知y是x的一次函數(shù)，且當(dāng)x=8時，y=15：當(dāng)x=－10時，y=－3，/r/n求：/r/n⑴/r/n這個一次函數(shù)的解析式；/r/n⑵/r/n當(dāng)y=－2時，求x的值；/r/n⑶/r/n若x的取值范圍是－2＜x＜3，求y的取值范圍./r/n⑷/r/n求直線與兩坐標(biāo)軸圍成的三角形面積/r/n34．/r/n一農(nóng)民帶上若干千克自產(chǎn)的土豆進(jìn)城出售,為了方便,他帶了一些零錢備用,按市場價售出一些后,又降價出售,售出的土豆千克數(shù)/r/n與他手中持有的錢數(shù)(含備用零錢)/r/n的關(guān)系,如圖所示,結(jié)合圖象回答下列問題：/r/n(1)農(nóng)民自帶的零錢是多少?/r/n(2)試求降價前/r/n與/r/n之間的關(guān)系式./r/n(3)由表達(dá)式你能求出降價前每千克的土豆價格是多少?/r/n(