9 phần x+3 = 8phần x-1
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22 tháng 3 2023
a: a=-8
b: Khi x=-4 thì y=-8/-4=2
Khi x=8 thì y=-8/8=-1
2 tháng 3 2023
a: =>(x-2)(3x+1)-(x-2)(x+2)=0
=>(x-2)(3x+1-x-2)=0
=>(x-2)(2x-1)=0
=>x=1/2 hoặc x=2
b: =>3(x-1)+4(x+1)=6(x-1)
=>3x-3+4x+4=6x-6
=>7x+1=6x-6
=>x=-7
c: =>x(x-3)-(x+2)(x+3)+16=0
=>x^2-3x-x^2-5x-6+16=0
=>10-8x=0
=>x=5/4
B
31 tháng 8 2020
Bài làm :
1)\(\frac{3}{2}+\frac{5}{2}-\frac{4}{2}=\frac{3+5-4}{2}=\frac{4}{2}=2\)
2)\(\frac{2}{5}\times\frac{1}{2}\div\frac{1}{3}=\frac{2\times1\times3}{5\times2\times1}=\frac{6}{10}=\frac{3}{5}\)
3)\(\frac{2}{9}\div\frac{9}{2}\times\frac{1}{2}=\frac{2\times2\times1}{9\times9\times2}=\frac{4}{162}=\frac{2}{81}\)
4)\(\left(\frac{4}{11}+\frac{3}{11}\right)\times\frac{2}{6}=\frac{4+3}{11}\times\frac{2}{6}=\frac{7}{11}\times\frac{2}{6}=\frac{7\times2}{11\times6}=\frac{14}{66}=\frac{7}{33}\)
H
9 tháng 2 2023
\(a,\dfrac{2x-1}{3}-\dfrac{5x+2}{7}=x+13\\ \Rightarrow7.\left(2x-1\right)-3.\left(5x+2\right)=21.\left(x+13\right)\\ \Rightarrow14x-7-15x-6=21x+273\\\Rightarrow -x-21x=273+13\\ \Rightarrow-22x=286\\ \Rightarrow x=-13\\ b,\dfrac{3\left(x+3\right)}{4}+\dfrac{1}{2}=\dfrac{5x+9}{3}-\dfrac{7x-9}{4}=0\\ \Rightarrow9.\left(x+3\right)+6=4.\left(5x+9\right)-3.\left(7x-9\right)=0\\\Rightarrow 9x+27+6=20x+36-21x+27\\ \Rightarrow9x+33=-x+63\\ \Rightarrow10x=30\\ \Rightarrow x=3\)
Y
9 tháng 2 2023
\(a,\dfrac{2x-1}{3}-\dfrac{5x+2}{7}=x+13\)
\(\Rightarrow7\left(2x-1\right)-3\left(5x+2\right)-21x-273=0\)
\(\Rightarrow14x-7-15x-6-21x-273=0\)
\(\Rightarrow-22x=286\)
\(\Rightarrow x=-13\)
\(b,\dfrac{3\left(x+3\right)}{4}+\dfrac{1}{2}=\dfrac{5x+9}{3}-\dfrac{7x-9}{4}\)
\(\Rightarrow9\left(x+3\right)+6-4\left(5x+9\right)+3\left(7x-9\right)=0\)
\(\Rightarrow9x+27+6-20x-36+21x-27=0\)
\(\Rightarrow10x=30\Rightarrow x=3\)
30 tháng 4 2017
\(\frac{3}{2}\)\(+\)\(\frac{5}{2}\)\(-\)\(\frac{4}{2}\)\(=\)\(\left(\frac{3}{2}+\frac{5}{2}\right)-\frac{4}{2}\)
\(=\frac{8}{2}-\frac{4}{2}=\frac{4}{2}=2\)
30 tháng 4 2017
\(\frac{2}{5}\)\(x\)\(\frac{1}{2}\)\(:\)\(\frac{1}{3}\)\(=\)\(\left(\frac{2}{5}x\frac{1}{2}\right)\)\(:\)\(\frac{1}{3}\)
\(=\)\(\frac{2}{10}\)\(:\)\(\frac{1}{3}\)\(=\frac{2}{10}x\frac{3}{1}\)\(=\frac{6}{10}=\frac{3}{5}\)
AT
26 tháng 4 2018
heoheo lần sau bạn đánh = kí hiệu đi :(((
a/ \(\dfrac{x}{3}+\dfrac{2x-1}{6}=\dfrac{1}{2}\)
\(\Leftrightarrow2x+2x-1=3\)
<=> 4x = 4 <=> x = 1
Vậy x = 1
b/ \(\dfrac{3x+1}{2}+\dfrac{x-1}{3}=\dfrac{x-9}{6}\)
\(\Leftrightarrow3\left(3x+1\right)+2\left(x-1\right)=x-9\)
\(\Leftrightarrow9x+3+2x-2=x-9\)
\(\Leftrightarrow10x=-10\Leftrightarrow x=-1\)
Vậy pt có nghiệm x = -1
c/ \(\dfrac{x-1}{x-2}=\dfrac{x+3}{x+2}\) ĐKXĐ: \(x\ne\pm2\)
<=> \(\left(x-1\right)\left(x+2\right)=\left(x+3\right)\left(x-2\right)\)
\(\Leftrightarrow x^2+2x-x-2=x^2-2x+3x-6\)
\(\Leftrightarrow0x=-4\left(voly\right)\)
Vậy pt vô nghiệm
d/ \(\dfrac{3x-1}{3x+1}+\dfrac{x-3}{x+3}=2\) ĐKXĐ: \(\left\{{}\begin{matrix}x\ne-3\\x\ne-\dfrac{1}{3}\end{matrix}\right.\)
pt <=> \(\dfrac{\left(3x-1\right)\left(x+3\right)}{\left(3x+1\right)\left(x+3\right)}+\dfrac{\left(x-3\right)\left(3x+1\right)}{\left(3x+1\right)\left(x+3\right)}=\dfrac{2\left(3x+1\right)\left(x+3\right)}{\left(3x+1\right)\left(x+3\right)}\)
=> (3x-1)(x+3) + (x-3)(3x+1) = 2(3x+1)(x+3)
\(\Leftrightarrow3x^2+8x-3+3x^2-8x-3=6x^2+20x+6\)
\(\Leftrightarrow-20x=12\Leftrightarrow x=-\dfrac{3}{5}\left(tm\right)\)
Vậy pt có nghiệm x=....
e/ như ý d
\(\dfrac{9}{x+3}=\dfrac{8}{x-1}\) (ĐK: x ≠ 1;-3)
\(\Leftrightarrow9\left(x-1\right)=8\left(x+3\right)\)
\(\Leftrightarrow9x-9=8x+24\)
\(\Leftrightarrow9x-8x=24+9\)
\(\Leftrightarrow x=33\) (TMĐK)