列明步驟及解釋
因式分解:
1.(a-b)二次- a+b
2.(x-5)(3x-2)+10(5-x)
3.x(a-x)(y+a)-3y(x-a)(a+y)
代數分式:
1.1 over m- 1over m+1
2.1 over p+2q + 1 over p-2q
3.x+1 over x+2- x over x+1
4.(p+q)(p-q) over (q-p)(p+4q)
5.3x-3x三次 over (1-x二次)(x-1)
6.1-a over 1+a÷a二次-a over a+a二次 乘 a二次+1 over 2a
率+比:
a.化簡
1.2.5min:100s
2.1 over 5:1 over 3:1 over 4
b.求未知數
1.若5x=3y及11y=3z,求x:y:z
2.一三角形的邊比是5:6:7.若最長邊長度為28cm,則該三角形的周 界是多少?
3.三個數的比為5:6:7,它們的和是540,求最大數的值.
c.率
1.子明可在12s內跑100m.問他以相同速率在一分鐘內可跑多遠?
2.一輛汽車行420km用30L油
a )該汽車每升油平均可走多遠
b) 行1km需油多少
c) 行546km需油多少
3.runner以12s跑100m
a)求速率
b)若他以平均速率跑步,求
i)跑40m的時間
ii)15s所跑的距離
4.如果10個工人可在6天內完成某項工作,問4個工人需時多久才可完成該工作?
中二數學題(20)
2008-12-23 4:38 am
回答 (2)
2008-12-23 9:51 am
✔ 最佳答案
因式分解:1.
(a-b)^2- a+b
=(a-b)^2-(a-b)
=(a-b)(a-b-1)
2.
(x-5)(3x-2)+10(5-x)
=(x-5)(3x-2)-10(x-5)
=(x-5)(3x-2-10)
=(x-5)(3x-12)
=3(x-5)(x-4)
3.
x(a-x)(y+a)-3y(x-a)(a+y)
=x(a-x)(a+y)+3y(a-x)(a+y)
=(a-x)(a+y)(x+3y)
代數分式:
1.
1/m- 1/m+1
=(m+1-1)/[m(m+1)]
=1/m(m+1)
2.
1/(p+2q) + 1/(p-2q)
=(p-2q+p+2q)/(p+2q)(p-2q)
=2p/(p+2q)(p-2q)
3.
x+1/(x+2)- x/(x+1)
=[(x+1)^2-x(x+2)]/(x+1)(x+2)
=(x^2+2x+1-x^2-2x)/(x+1)(x+2)
1/(x+1)(x+2)
4.
(p+q)(p-q)/(q-p)(p+4q)
= -(p+q)/(p+4q)
5.
(3x-3x^3)/(1-x^2)(x-1)
3x(1-x^2)/(1-x^2)(x-1)
=3x/(x+1)
6.不知你說什麼
率+比:
1.
2.5min:100s
=2.5*60:100
=150:100
=3:2
2.
1/5:1/3:1/4
=12:20:15
b.
1.
x:y=3:5 y:x=3:11
x:y:z=9:15:55
2.
5:6:7=x:y:28
x=20 y=24
周界=20+24+28=72cm
3.
5x+6x+7x=540
18x=540
x=30
最大=7x=210
c.率
1.
12:100=60:x
x=500
一分鐘可跑500m
2.一輛汽車行420km用30L油
a )每升油平均可走
=420/30
=14km
b) 行1km需油
=30/420
=1/14
c) 行546km需油
=546*1/14
=39L
3.runner以12s跑100m
a)速率
=100/12
=25/3米每秒
b)i)
12:100=x:40
x=4.8
跑40m需要4.8秒
ii)15s所跑的距離
=15*25/3
=125m
4.
10=2+4+4
需時:3+6+6=15天
參考: me
2008-12-24 6:40 pm
因式分解:
1.(a-b)^2- a+b
=(a-b)^2-(a-b)
=(a-b)(a-b-1)
2.(x-5)(3x-2)+10(5-x)
=(x-5)(3x-2)-10(x-5)
=(x-5)(3x-2-10)
=(x-5)(3x-12)
=3(x-5)(x-4)
3.x(a-x)(y+a)-3y(x-a)(a+y)
=x(a-x)(a+y)+3y(a-x)(a+y)
=(a-x)(a+y)(x+3y)
代數分式:
1.1/m- 1/m+1
=(m+1-1)/[m(m+1)]
=1/m(m+1)
2.1/(p+2q) + 1/(p-2q)
=(p-2q+p+2q)/(p+2q)(p-2q)
=2p/(p+2q)(p-2q)
3.x+1/(x+2)- x/(x+1)
=[(x+1)^2-x(x+2)]/(x+1)(x+2)
=(x^2+2x+1-x^2-2x)/(x+1)(x+2)
1/(x+1)(x+2)
4.(p+q)(p-q)/(q-p)(p+4q)
= -(p+q)/(p+4q)
5.(3x-3x^3)/(1-x^2)(x-1)
3x(1-x^2)/(1-x^2)(x-1)
=3x/(x+1)
6.不明白你說什麼?
率+比:
1.2.5min:100s
=2.5*60:100
=150:100
=3:2
2.1/5:1/3:1/4
=12:20:15
b.?
1.x:y=3:5 y:x=3:11
x:y:z=9:15:55
2.5:6:7=x:y:28
x=20 y=24
周界=20+24+28=72cm
3.5x+6x+7x=540
18x=540
x=30
最大=7x=210
c.率
1.12:100=60:x
x=500
一分鐘可跑500m
2.一輛汽車行420km用30L油
a )每升油平均可走
=420/30
=14km
b) 行1km需油
=30/420
=1/14
c) 行546km需油
=546*1/14
=39L
3.runner以12s跑100m
a)速率
=100/12
=25/3米每秒
b)i)12:100=x:40
x=4.8
跑40m需要4.8秒
ii)15s所跑的距離
=15*25/3
=125m
4.10=2+4+4
需時:3+6+6=15天
1.(a-b)^2- a+b
=(a-b)^2-(a-b)
=(a-b)(a-b-1)
2.(x-5)(3x-2)+10(5-x)
=(x-5)(3x-2)-10(x-5)
=(x-5)(3x-2-10)
=(x-5)(3x-12)
=3(x-5)(x-4)
3.x(a-x)(y+a)-3y(x-a)(a+y)
=x(a-x)(a+y)+3y(a-x)(a+y)
=(a-x)(a+y)(x+3y)
代數分式:
1.1/m- 1/m+1
=(m+1-1)/[m(m+1)]
=1/m(m+1)
2.1/(p+2q) + 1/(p-2q)
=(p-2q+p+2q)/(p+2q)(p-2q)
=2p/(p+2q)(p-2q)
3.x+1/(x+2)- x/(x+1)
=[(x+1)^2-x(x+2)]/(x+1)(x+2)
=(x^2+2x+1-x^2-2x)/(x+1)(x+2)
1/(x+1)(x+2)
4.(p+q)(p-q)/(q-p)(p+4q)
= -(p+q)/(p+4q)
5.(3x-3x^3)/(1-x^2)(x-1)
3x(1-x^2)/(1-x^2)(x-1)
=3x/(x+1)
6.不明白你說什麼?
率+比:
1.2.5min:100s
=2.5*60:100
=150:100
=3:2
2.1/5:1/3:1/4
=12:20:15
b.?
1.x:y=3:5 y:x=3:11
x:y:z=9:15:55
2.5:6:7=x:y:28
x=20 y=24
周界=20+24+28=72cm
3.5x+6x+7x=540
18x=540
x=30
最大=7x=210
c.率
1.12:100=60:x
x=500
一分鐘可跑500m
2.一輛汽車行420km用30L油
a )每升油平均可走
=420/30
=14km
b) 行1km需油
=30/420
=1/14
c) 行546km需油
=546*1/14
=39L
3.runner以12s跑100m
a)速率
=100/12
=25/3米每秒
b)i)12:100=x:40
x=4.8
跑40m需要4.8秒
ii)15s所跑的距離
=15*25/3
=125m
4.10=2+4+4
需時:3+6+6=15天
收錄日期: 2021-04-13 16:19:09
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081222000051KK01725