Giải phương trình \(\frac{x-1}{3}+\frac{x+3}{x}=2\)
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1) \(\frac{x-1}{x+3}-\frac{x}{x-3}=\frac{4x+15}{9-x^2}\)
ĐKXĐ : \(x\ne\pm3\)
\(\Leftrightarrow\frac{x-1}{x+3}-\frac{x}{x-3}=\frac{-4x-15}{x^2-9}\)
\(\Leftrightarrow\frac{\left(x-1\right)\left(x-3\right)}{\left(x-3\right)\left(x+3\right)}-\frac{x\left(x+3\right)}{\left(x-3\right)\left(x+3\right)}=\frac{-4x-15}{\left(x-3\right)\left(x+3\right)}\)
\(\Leftrightarrow\frac{x^2-4x+3}{\left(x-3\right)\left(x+3\right)}-\frac{x^2+3x}{\left(x-3\right)\left(x+3\right)}=\frac{-4x-15}{\left(x-3\right)\left(x+3\right)}\)
\(\Leftrightarrow\frac{x^2-4x+3-x^2-3x}{\left(x-3\right)\left(x+3\right)}=\frac{-4x-15}{\left(x-3\right)\left(x+3\right)}\)
\(\Leftrightarrow-7x+3=-4x-15\)
\(\Leftrightarrow-7x+4x=-15-3\)
\(\Leftrightarrow-3x=-18\)
\(\Leftrightarrow x=6\)( tmđk )
Vậy x = 6 là nghiệm của phương trình
2) 2x + 3 < 6 - ( 3 - 4x )
<=> 2x + 3 < 6 - 3 + 4x
<=> 2x - 4x < 6 - 3 - 3
<=> -2x < 0
<=> x > 0
Vậy nghiệm của bất phương trình là x > 0
\(a,\Leftrightarrow5\left(x-2\right)-15x\le9+10\left(x+1\right)\)
\(\Leftrightarrow5x-10-15x\le9+10x+10\)
\(\Leftrightarrow-20x\le29\)
\(\Leftrightarrow x\ge-1,45\)
Vậy ...........
\(b,\Rightarrow\left(x+2\right)-3\left(x-3\right)=5\left(x-2\right)\)
\(\Leftrightarrow x+2-3x+9-5x+10=0\)
\(\Leftrightarrow-7x+21=0\)
\(\Leftrightarrow x=3\)
Vậy ..............
\(\frac{x-2}{6}-\frac{x}{2}\le\frac{3}{10}+\frac{x+1}{3}\Leftrightarrow\frac{5\left(x-2\right)}{30}-\frac{15x}{30}\le\frac{9}{30}+\frac{10\left(x+1\right)}{30}\)
\(\Leftrightarrow5x-10-15x-9-10x-10\le0\)
\(\Leftrightarrow-20x-29\le0\Leftrightarrow\left(-20x\right)\cdot\frac{-1}{20}\ge29\cdot-\frac{1}{20}\)
\(\Leftrightarrow x\ge-\frac{29}{20}\)
Cái bài đầu giải BPT bn ghi cái dj ak ,mik cx k hỉu nữa
V mik giải bài 2 nghen, sửa lại đề bài đầu rồi mik giải cho
\(3x-3=|2x+1|\)
Điều kiện: \(3x-3\ge0\Leftrightarrow3x\ge3\Leftrightarrow x\ge1\)
\(\Leftrightarrow\orbr{\begin{cases}2x+1=3x-3\\2x+1=-3x+3\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x-3x=-1-3\\2x+3x=-1+3\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}-x=-3\\5x=2\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3\left(n\right)\\x=\frac{2}{5}\left(l\right)\end{cases}}}\)
Vậy S={3}
Cài đề câu b ,bn xem lại nhé!
\(\frac{2x-3}{35}+\frac{x\left(x-2\right)}{7}>\frac{x^2}{7}-\frac{2x-3}{5}\)
\(\Leftrightarrow\frac{2x-3}{35}+\frac{5x\left(x-2\right)}{35}-\frac{5x^2}{35}+\frac{7\left(2x-3\right)}{35}>0\)
\(\Leftrightarrow2x-3+5x\left(x-2\right)-5x^2+7\left(2x-3\right)>0\)
\(\Leftrightarrow2x-3+5x^2-10x-5x^2+14x-21>0\)
\(\Leftrightarrow6x-24>0\)
\(\Leftrightarrow x>4\)
VẬY TẬP NGHIỆM CỦA BẤT PHƯƠNG TRÌNH LÀ : S = { \(x\text{\x}>4\)}
\(\frac{6x+1}{18}+\frac{x+3}{12}\le\frac{5x+3}{6}+\frac{12-5x}{9}\)
\(\Leftrightarrow\frac{6\left(6x+1\right)}{108}+\frac{9\left(x+3\right)}{108}\le\frac{18\left(5x+3\right)}{108}+\frac{12\left(12-5x\right)}{108}\)
\(\Leftrightarrow36x+6+9x+27\le90x+54+144-60x\)
\(\Leftrightarrow36x+6+9x+27-90x-54-144+60x\le0\)
\(\Leftrightarrow15x-165\le0\)
\(\Leftrightarrow x\le11\)
VẬY TẬP NGHIỆM CỦA BẤT PHƯƠNG trình ..........
tk mk nka !!! chúc bạn học tốt !!!
\(\frac{2}{x^3-x^2-x+1}=\frac{3}{1-x^2}-\frac{1}{x+1}\)
<=> \(\frac{2}{\left(x^2-1\right)\left(x-1\right)}+\frac{3}{\left(x-1\right)\left(x+1\right)}+\frac{1}{x+1}=0\)
<=> \(\frac{2}{\left(x-1\right)^2\left(x+1\right)}+\frac{3\left(x-1\right)}{\left(x-1\right)^2\left(x+1\right)}+\frac{\left(x-1\right)^2}{\left(x-1\right)^2\left(x+1\right)}=0\)
<=> \(2+3x-3+x^2-2x+1=0\)
<=> x2 + x = 0
<=> x(x + 1) = 0
<=> \(\orbr{\begin{cases}x=0\\x+1=0\end{cases}}\)
<=> \(\orbr{\begin{cases}x=0\\x=-1\end{cases}}\)
Vậy S = {0; -1}
\(\frac{x+2}{x+1}+\frac{3}{x-2}=\frac{3}{x^2-x-x}+1\)
\(\Leftrightarrow\frac{\left(x+2\right)\left(x-2\right)}{\left(x+1\right)\left(x-2\right)}+\frac{3\left(x+1\right)}{\left(x-2\right)\left(x+1\right)}=\frac{3}{\left(x+1\right)\left(x-2\right)}+\frac{\left(x+1\right)\left(x-2\right)}{\left(x+1\right)\left(x-2\right)}\)
\(\Rightarrow x^2-4+3x+3=3+x^2-2x+x-2\)
\(\Leftrightarrow x^2-x^2+3x+2x-x=1+4-3\)
\(\Leftrightarrow4x=2\)
\(\Leftrightarrow x=\frac{1}{2}\)
Điều kiện: x khác (-3,-2,1,4)
PT <=>
\(1+\frac{2}{x-1}+1-\frac{4}{x+2}+1-\frac{6}{x+3}+1+\frac{8}{x-4}=4\)
<=> \(\frac{1}{x-1}-\frac{2}{x+2}-\frac{3}{x+3}+\frac{4}{x-4}=0\)
<=> (x+2)(x+3)(x-4)-2(x-1)(x+3)(x-4)-3(x-1)(x+2)(x-4)+4(x-1)(x+2)(x+3)=0
<=> (x3+x2-14x-24)-2(x3 - 2x2-11x+12) - 3(x3 - 3x2- 6x+8) + 4(x3+4x2 + x-6) = 0
<=> x3+x2-14x-24-2x3 + 4x2+22x-24 - 3x3 + 9x2+ 18x-24 + 4x3+16x2 + 4x-24 = 0
<=> 30x2 + 30x -96=0
<=> 5x2 + 5x -16 = 0
Giải ra được: \(\orbr{\begin{cases}x_1=\frac{-5-\sqrt{345}}{10}\\x_2=\frac{-5+\sqrt{345}}{10}\end{cases}}\)
\(\frac{x+2}{x+1}+\frac{3}{x-2}=\frac{3}{x^2-x-2}+1\)
\(\frac{\left(x+2\right)\left(x-2\right)+3\left(x+1\right)}{x^2-x-2}=\frac{3+x^2-x-2}{x^2-x-2}\)
\(x^2-4+3x+3=1+x^2-x\)
\(x^2+3x-1-1-x^2+x=0\)
\(4x-2=0\)
\(4x=2\Leftrightarrow x=\frac{1}{2}\)
Vậy.....
\(\frac{x+2}{x+1}+\frac{3}{x-2}=\frac{3}{x^2-x-2}+1\)
\(\Leftrightarrow\)\(\frac{x+2}{x+1}+\frac{3}{x-2}=\frac{3}{\left(x+1\right).\left(x-2\right)}+1\)
ĐKXĐ: \(x\ne-1,2\)
\(\frac{\left(x+2\right).\left(x-2\right)}{\left(x+1\right).\left(x-2\right)}+\)\(\frac{3.\left(x+1\right)}{\left(x+1\right).\left(x-2\right)}=\)\(\frac{3}{\left(x+1\right).\left(x-2\right)}+\frac{\left(x+1\right).\left(x-2\right)}{\left(x+1\right).\left(x-2\right)}\)
\(\Leftrightarrow\) \(\left(x^2-4\right)\) \(+3.\left(x+1\right)=\)\(3+\left(x+1\right).\left(x-2\right)\)
\(\Leftrightarrow\) x2 - 4 + 3x + 3 = 3 + x2 - x - 2
\(\Leftrightarrow\) x2 + 3x - x2 + x = 4 - 3 + 3 - 2
\(\Leftrightarrow\) 4x = 2
\(\Leftrightarrow\)\(x=\frac{1}{2}\)
Vậy phương trình có nghiệm là: \(x=\frac{1}{2}\)
\(x-\frac{\frac{x}{2}-\frac{3+x}{4}}{2}=3-\frac{\left(1-\frac{6-x}{3}\right).\frac{1}{2}}{2}\)
\(\Leftrightarrow2x-\frac{x}{2}+\frac{3+x}{4}=6-\frac{1}{2}+\frac{6-x}{6}\)
\(\Leftrightarrow24x-6x+9+3x=72-6+12-2x\)
\(\Leftrightarrow23x=69\)
\(\Leftrightarrow x=3\)
Vậy nghiệm của pt x=3
\(ĐKCĐ:x\ne0\)
\(\frac{x-1}{3}+\frac{x+3}{x}=2\)
\(\Leftrightarrow\)\(\frac{x\left(x-1\right)+3\left(x+3\right)}{3x}=2\)
\(\Leftrightarrow\)\(x\left(x-1\right)+3\left(x+3\right)=6x\)
\(\Leftrightarrow\)\(x^2-x+3x+9=6x\)
\(\Leftrightarrow\)\(x^2-x+3x-6x+9=0\)
\(\Leftrightarrow\)\(x^2-4x+9=0\)
\(\Leftrightarrow\)\(\left(x-2\right)^2+5=0\)
\(\Leftrightarrow\)\(\left(x-2\right)^2=-5\)\(\rightarrow\)Vô Lý
Vậy pt vô nghiễm-1/
KL là vậy pt vô nghiệm thôi nhé