làm hộ bài 1 với
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Bài 1:
a: =8xy/2x=4y
b: \(=\dfrac{4x-1-7x+1}{3x^2y}=\dfrac{-3x}{3x^2y}=\dfrac{-1}{xy}\)
c: \(=\dfrac{3x-x+6}{2x\left(x+3\right)}=\dfrac{2\left(x+3\right)}{2x\left(x+3\right)}=\dfrac{1}{x}\)
e: \(=\dfrac{5\left(x+2\right)}{4\left(x-2\right)}\cdot\dfrac{-2\left(x-2\right)}{x+2}=\dfrac{-10}{4}=-\dfrac{5}{2}\)
Bài 1.
\(2Fe+3Cl_2\underrightarrow{t^o}2FeCl_3\)
\(Fe_2O_3+3H_2SO_4\rightarrow Fe_2\left(SO_4\right)_3+3H_2O\)
\(H_2SO_4+H_2S\rightarrow2S+2H_2O\)
\(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\)
b: \(=8+2\cdot3-7\cdot1.3+3\cdot\dfrac{5}{4}=8.65\)
Bài 1:
b) \(B=A.\dfrac{-10}{x-4}=\dfrac{x-4}{x+5}.\dfrac{-10}{x-4}=\dfrac{-10}{x+5}\)
Để B nguyên <=> x+5 nguyên mà \(x\in Z\Rightarrow x+5\inƯ\left(-10\right)=\left\{\pm1;\pm2;\pm5;\pm10\right\}\)
\(\Leftrightarrow x\in\left\{-6;-4;-3;-7;0;-10;-15;5\right\}\) kết hợp với điều kiện của x
\(\Rightarrow x\in\left\{-15;-10;-6;-7;-3;0;5\right\}\)
Bài 5:
Có \(\left|x-2018\right|+\left|2x-2019\right|+\left|3x-2020\right|\ge0\) \(\forall\)x
\(\Rightarrow x-2021\ge0\) \(\Leftrightarrow x\ge2021\)
\(\Rightarrow x-2018>0,2x-2019>0,3x-2020>0\)
PT \(\Leftrightarrow x-2018+2x-2019+3x-2020=x-2021\)
\(\Leftrightarrow5x=4036\) \(\Leftrightarrow x=\dfrac{4036}{5}< 2021\) (L)
Vậy pt vô nghiệm
đề là tìm n nguyên để biểu thức nguyên hả bạn ?
d, \(\frac{3n+1}{n-2}=\frac{3\left(n-2\right)+7}{n-2}=3+\frac{7}{n-2}\)ĐK : \(n\ne2\)
\(\Rightarrow n-2\inƯ\left(7\right)=\left\{\pm1;\pm7\right\}\)
n - 2 | 1 | -1 | 7 | -7 |
n | 3 | 1 | 9 | -5 |
tương tự
I. Write sentences with the cues given
1. Mai / usually / listen / K - pop music / free time.
→ Mai usually listens to K-pop music in her free time.
2. when / I / be / a child / I / enjoy / play / computer games
→ When I was a child, I enjoyed playing computer games.
3. my father / spend / most / spare time / look after / the garden
→ My father spends most of his spare time looking after the garden.
4. watching TV / most / popular / leisure activity / Britain ?
→ Is watching TV the most popular leisure activity in Britain?
5. many teenagers / addicted / the Internet / computer games
→ Many teenagers are addicted to the Internet and computer games.
6. she / get / hooked / the medical drama / after / watch / the first people
→ She got hooked on the medical drama after watching the first episode.
7. most / my friends / prefer / play sports / to / surf the net
→ Most of my friends prefer to play sports rather than surf the net.
8. today's world / teenagers / rely / technology / more / the past
→ In today's world, teenagers rely on technology more than in the past
II. Write the second sentences so that it has a similar meaning to the first one
1. It takes us more than two hours to see the film " Avatar "
→ The film " Avatar " requires more than two hours of our time to watch.
2. She likes to hang out with friends on Saturday evening
→ She's interested in socializing with friends on Saturday evening
Bài 1 :
\(a,P=\dfrac{3x^2+3x}{\left(x+1\right)\left(2x-6\right)}\left(dkxd:x\ne-1;3\right)\)
\(=\dfrac{3x\left(x+1\right)}{\left(x+1\right)\left(2x-6\right)}\)
\(=\dfrac{3x}{2x-6}\)
Để P = 1 thì :
\(\dfrac{3x}{2x-6}=1\)
\(\Leftrightarrow\dfrac{3x-2x+6}{2x-6}=0\)
\(\Leftrightarrow x=-6\)
Bài 1 :
a) ĐKXĐ : `x \ne -1 ; x \ne 3`
b)
`P = ( 3x^2 + 3x )/((x+1)(2x-6))`
`P=(3x( x + 1 ))/((x+1)(2x-6))`
`P=(3x)/(2x-6)`
Để `P = 1 <=> (3x)/(2x-6)=1`
`<=> 3x=2x-6`
`<=> 2x-3x=6`
`<=> -x=6`
`<=> x=-6` ( tm )
Vậy `x=-6`