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3 tháng 3 2020
a, \(\frac{1-x}{x+1}+3=\frac{2x+3}{x+1}\)
\(=>\frac{1-x+x+1}{x+1}+2=\frac{1}{x+1}+2\)
\(=>\frac{2}{x+1}=\frac{1}{x+1}\)
\(=>2x+2=x+1\)
\(=>2x-x=1-2=-1\)
\(=>x=-1\)
vậy nghiệm của phương trình trên là {-1}
3 tháng 3 2020
À quên ĐKXĐ của câu a là \(x\ne-1\)
Nên \(x\in\varnothing\)nhé :v
L
20 tháng 1 2019
a) <=> \(6x^2-5x+3-2x+3x\left(3-2x\right)=0\)
<=> \(6x^2-5x+3-2x+9x-6x^2=0\)
<=> \(2x+3=0\)
<=> \(x=\frac{-3}{2}\)
b) <=> \(10\left(x-4\right)-2\left(3+2x\right)=20x+4\left(1-x\right)\)
<=> \(10x-40-6-4x=20x+4-4x\)
<=> \(6x-46-16x-4=0\)
<=> \(-10x-50=0\)
<=> \(-10\left(x+5\right)=0\)
<=> \(x+5=0\)
<=> \(x=-5\)
c) <=> \(8x+3\left(3x-5\right)=18\left(2x-1\right)-14\)
<=> \(8x+9x-15=36x-18-14\)
<=> \(8x+9x-36x=+15-18-14\)
<=> \(-19x=-14\)
<=> \(x=\frac{14}{19}\)
d) <=>\(2\left(6x+5\right)-10x-3=8x+2\left(2x+1\right)\)
<=> \(12x+10-10x-3=8x+4x+2\)
<=> \(2x-7=12x+2\)
<=> \(2x-12x=7+2\)
<=> \(-10x=9\)
<=> \(x=\frac{-9}{10}\)
e) <=> \(x^2-16-6x+4=\left(x-4\right)^2\)
<=> \(x^2-6x-12-\left(x-4^2\right)=0\)
<=> \(x^2-6x-12-\left(x^2-8x+16\right)=0\)
<=> \(x^2-6x-12-x^2+8x-16=0\)
<=> \(2x-28=0\)
<=> \(2\left(x-14\right)=0\)
<=> x-14=0
<=> x=14
6 tháng 2 2018
\(\frac{2}{x-1}+\frac{2x+3}{x^2+x+1}=\frac{\left(2x-1\right)\left(2x+1\right)}{x^3-1}\)
Quy đồng mẫu chung :
\(\frac{2.\left(x^2+x+1\right)}{\left(x-1\right)\left(x^2+x+1\right)}+\frac{\left(2x+3\right)\left(x-1\right)}{\left(x-1\right)\left(x^2+x+1\right)}=\frac{\left(4x^2-1\right)}{\left(x-1\right)\left(x^2+x+1\right)}\)
Sau đó ta khử mẫu:
\(\Rightarrow\)\(2x^2+2x+2+2x^2+x-3=4x^2-1\)
\(\Rightarrow\)\(2x^2+2x+2x^2+x-4x^2=-1-2+3\)
\(\Rightarrow\)\(3x=0\)
\(\Rightarrow\)\(x=0\)
Vậy bạn tự kết luận
KT
6 tháng 2 2018
ĐKXĐ: \(x\ne1\)
\(\frac{2}{x-1}+\frac{2x+3}{x^2+x+1}=\frac{\left(2x-1\right)\left(2x+1\right)}{x^3-1}\)
\(\Leftrightarrow\)\(\frac{2\left(x^2+x+1\right)}{\left(x-1\right)\left(x^2+x+1\right)}+\frac{\left(2x+3\right)\left(x-1\right)}{\left(x-1\right)\left(x^2+x+1\right)}=\frac{4x^2-1}{x^3-1}\)
\(\Leftrightarrow\)\(\frac{2x^2+2x+2}{x^3-1}+\frac{2x^2+x-3}{x^3-1}=\frac{4x^2-1}{x^3-1}\)
\(\Rightarrow\)\(2x^2+2x+2+2x^2+x-3=4x^2-1\)
\(\Leftrightarrow\)\(4x^2+3x-1=4x^2-1\)
\(\Leftrightarrow\)\(3x=0\)
\(\Leftrightarrow\)\(x=0\) (thỏa mãn)
Vậy....
O
6 tháng 5 2019
a)\(\frac{x+3}{6}\)+\(\frac{x-2}{10}\)>\(\frac{x+1}{5}\)
<=> \(\frac{5\left(x+3\right)}{30}\)+\(\frac{3\left(x-2\right)}{30}\)>\(\frac{6\left(x+1\right)}{30}\)
<=>5(x+3)+3(x-2)>6(x+1)
<=>5x+15+3x-6>6x+6
<=>8x-6x >6-15+6
<=>2x >-3
<=>x >-1,5
Vậy tập nghiệm của bất phương trình là {x/x>-1,5}
HN
15 tháng 1 2019
a, \(\frac{\left(x-2\right)^2}{3}-\frac{\left(2x-3\right).\left(2x+3\right)}{8}+\frac{\left(x-4\right)^2}{6}=0\)
\(\Leftrightarrow\frac{x^2-4x+4}{3}+\frac{9-4x^2}{8}+\frac{x^2-8x+16}{6}=0\)
\(\Leftrightarrow\frac{8\left(x^2-4x+4\right)+3\left(9-4x^2\right)+4\left(x^2-8x+16\right)}{24}=0\)
\(\Leftrightarrow\frac{8x^2-32x+32+27-12x^2+4x^2-32x+64}{24}=0\)
\(\Leftrightarrow\frac{123-64x}{24}=0\Leftrightarrow123-64x=0\Leftrightarrow x=\frac{123}{64}\)
LN
1
MC
18 tháng 2 2020
\(\frac{x}{2\left(x-3\right)}+\frac{x}{2\left(x+1\right)}-\frac{2x}{\left(x+1\right)\left(x+3\right)}=0\)
\(\frac{x\left(x+1\right)}{2\left(x-3\right)\left(x+1\right)}+\frac{x\left(x-3\right)}{2\left(x-3\right)\left(x+1\right)}-\frac{2.2x}{2\left(x-3\right)\left(x+1\right)}=0\)
\(\frac{x^2+x}{2\left(x-3\right)\left(x+1\right)}+\frac{x^2-3x}{2\left(x-3\right)\left(x+1\right)}-\frac{4x}{2\left(x-3\right)\left(x+1\right)}=0\)
\(\frac{x^2+x+x^2-3x-4x}{2\left(x-3\right)\left(x+1\right)}=0\)
\(\frac{2x^2-6x}{2\left(x-3\right)\left(x+1\right)}=0\)
=>\(2x^2-6x=0\)
\(2x\left(x-3\right)=0\)
=>\(x=0\)
\(x=3\)
18 tháng 6 2017
b) \(\frac{x-3}{x-2}+\frac{x+2}{x-4}=-1\)
\(\Rightarrow\frac{\left(x-3\right)\left(x-4\right)}{\left(x-2\right)\left(x-4\right)}+\frac{\left(x-2\right)\left(x-2\right)}{\left(x-2\right)\left(x-4\right)}=-1\)
\(\Rightarrow\frac{\left(x-3\right)\left(x-4\right)+x^2-4}{\left(x-2\right)\left(x-4\right)}=-1\)
\(\Rightarrow\frac{x^2-7x+12+x^2-4}{\left(x-2\right)\left(x-4\right)}=-1\)
\(\Rightarrow\frac{2x^2-7x+8}{\left(x-2\right)\left(x-4\right)}=-1\)
\(\Rightarrow\frac{2x^2-7x+8}{\left(x-2\right)\left(x-4\right)}=-1\)
.................
18 tháng 6 2017
a) \(\frac{2}{x-1}+\frac{2x+3}{x^2+x+1}=\frac{\left(2x-1\right)\left(2x+1\right)}{x^3-1}\)
\(\Rightarrow\frac{2\left(x^2+x+1\right)}{\left(x-1\right)\left(x^2+x+1\right)}+\frac{\left(2x+3\right)\left(x-1\right)}{\left(x+1\right)\left(x^2+x+1\right)}=\frac{\left(2x-1\right)\left(2x+1\right)}{x^3-1}\)
\(\Rightarrow\frac{2\left(x^2+x+1\right)+\left(2x+3\right)\left(x-1\right)}{x^3-1}=\frac{\left(2x-1\right)\left(2x+1\right)}{x^3-1}\)
\(\Rightarrow\left(x^3-1\right)\left[2\left(x^2+x+1\right)+\left(2x+3\right)\left(x-1\right)\right]=\left(x^3-1\right)\left(2x-1\right)\left(2x+1\right)\)
\(\Rightarrow2\left(x^2+x+1\right)+\left(2x+3\right)\left(x-1\right)=\left(2x-1\right)\left(2x+1\right)\)
\(\Rightarrow2\left(x^2+x+1\right)+\left(2x+3\right)\left(x-1\right)-\left(2x-1\right)\left(2x+1\right)=0\)
\(\Rightarrow2x^2+2x+2+2x^2-2x+3x-3-\left(4x^2-1\right)=0\)
\(\Rightarrow2x^2+2x+2+2x^2-2x+3x-3-4x^2+1=0\)
\(\Rightarrow3x=0\)
\(\Rightarrow luon-dung-voi-moi-x\)
\(ĐKXĐ:x\ne\frac{3}{2}\)
\(\frac{\left(x+2\right)^2}{2x-3}-1=\frac{x^2+10}{2x-3}\)
\(\Leftrightarrow\frac{x^2+4x+4-2x+3}{2x-3}=\frac{x^2+10}{2x-3}\)
\(\Leftrightarrow x^2+2x+7=x^2+10\)
\(\Leftrightarrow2x=3\)
\(\Leftrightarrow x=\frac{3}{2}\left(KTMĐKXĐ\right)\)
Vậy phương trình vô nghiệm
ĐKXĐ: x khác 3/2
\(\frac{\left(x+2\right)^2}{2x-3}-1=\frac{x^2+10}{2x-3}\)
<=> \(\frac{x^2+4x+4}{2x-3}-1=\frac{x^2+10}{2x-3}\)
<=> x^2 + 4x + 4 - 2x + 3 = x^2 + 10
<=> x^2 + 4x + 4 - 2x + 3 - x^2 - 10 = 0
<=> 2x - 3 = 0
<=> 2x = 0 + 3
<=> 2x = 3
<=> x = 3 (ktmdk)
=> pt no