làm tính trừ \(\dfrac{4-x}{x^2+2}\)-\(\dfrac{x^2+5x}{x^3-x^2+2x-2}\)
Những câu hỏi liên quan
làm tính trừ \(\dfrac{5x+y}{xy-5x^2}\)-\(\dfrac{35x^2+8xy+y^2}{xy^225x^3}\)
thực hiện phép tính \(\dfrac{x^3+6x^2-25}{x^3+3x^2-10x}\)-\(\dfrac{x+5}{2x-x^2}\)
b: \(=\dfrac{x^3+6x^2-25}{x\left(x+5\right)\left(x-2\right)}+\dfrac{x+5}{x\left(x-2\right)}\)
\(=\dfrac{x^3+6x^2-25+x^2+10x+25}{x\left(x+5\right)\left(x-2\right)}=\dfrac{x^3+7x^2+10x}{x\left(x+5\right)\left(x-2\right)}=\dfrac{x+2}{x-2}\)
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Làm tính trừ phân thức :
a) dfrac{3x-2}{2xy}-dfrac{7x-4}{2xy}
b) dfrac{3x+5}{4x^3y}-dfrac{5-15x}{4x^3y}
c) dfrac{4x+7}{2x+2}-dfrac{3x+6}{2x+2}
d) dfrac{9x+5}{2left(x-1right)left(x+3right)^2}-dfrac{5x-7}{2left(x-1right)left(x+3right)^2}
e) dfrac{xy}{x^2-y^2}-dfrac{x^2}{y^2-x^2}
f) dfrac{5x+y^2}{x^2y}-dfrac{5y-x^2}{xy^2}
g)dfrac{x}{5x+5}-dfrac{x}{10x-10}
h) dfrac{x+9}{x^2-9}-dfrac{3}{x^2+3x}
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Làm tính trừ phân thức :
a) \(\dfrac{3x-2}{2xy}-\dfrac{7x-4}{2xy}\)
b) \(\dfrac{3x+5}{4x^3y}-\dfrac{5-15x}{4x^3y}\)
c) \(\dfrac{4x+7}{2x+2}-\dfrac{3x+6}{2x+2}\)
d) \(\dfrac{9x+5}{2\left(x-1\right)\left(x+3\right)^2}-\dfrac{5x-7}{2\left(x-1\right)\left(x+3\right)^2}\)
e) \(\dfrac{xy}{x^2-y^2}-\dfrac{x^2}{y^2-x^2}\)
f) \(\dfrac{5x+y^2}{x^2y}-\dfrac{5y-x^2}{xy^2}\)
g)\(\dfrac{x}{5x+5}-\dfrac{x}{10x-10}\)
h) \(\dfrac{x+9}{x^2-9}-\dfrac{3}{x^2+3x}\)
Làm tính cộng các phân thức sau :
a) \(\dfrac{5}{2x^2y}+\dfrac{3}{5xy^2}+\dfrac{x}{y^3}\)
b) \(\dfrac{x+1}{2x+6}+\dfrac{2x+3}{x\left(x+3\right)}\)
c) \(\dfrac{3x+5}{x^2-5x}+\dfrac{25-x}{25-5x}\)
d) \(x^2+\dfrac{x^4+1}{1-x^2}+1\)
e) \(\dfrac{4x^2-3x+17}{x^3-1}+\dfrac{2x-1}{x^2+x+1}+\dfrac{6}{1-x}\)
Bài 2:a) (x+1)(2x-3)-3(x-2)2(x-1)^2b) (x+1)(x^2-x+1)-2xx(x-1)(x+1)c) dfrac{x}{3}-dfrac{5x}{6}-dfrac{15x}{12}dfrac{x}{4}-5d) dfrac{x-1}{2}-dfrac{x+1}{15}-dfrac{2x-13}{6}0e) dfrac{3left(5x-2right)}{4}-2dfrac{7x}{3}-5(x-7)g) dfrac{x-3}{11}+dfrac{x+1}{3}dfrac{x+7}{9}-1h) dfrac{3x-0,4}{2}+dfrac{1,5-2x}{3}dfrac{x+0,5}{5}
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Bài 2:
a) (x+1)(2x-3)-3(x-2)
=2(x-1)\(^2\)
b) (x+1)(x\(^2\)-x+1)-2x
=x(x-1)(x+1)
c) \(\dfrac{x}{3}\)-\(\dfrac{5x}{6}\)-\(\dfrac{15x}{12}\)=\(\dfrac{x}{4}\)-5
d) \(\dfrac{x-1}{2}\)-\(\dfrac{x+1}{15}\)-
\(\dfrac{2x-13}{6}\)=0
e) \(\dfrac{3\left(5x-2\right)}{4}\)-2
=\(\dfrac{7x}{3}\)-5(x-7)
g) \(\dfrac{x-3}{11}\)+\(\dfrac{x+1}{3}\)
=\(\dfrac{x+7}{9}\)-1
h) \(\dfrac{3x-0,4}{2}\)+\(\dfrac{1,5-2x}{3}\)
=\(\dfrac{x+0,5}{5}\)
a) Ta có: \(\left(x+1\right)\left(2x-3\right)-3\left(x-2\right)=2\left(x-1\right)^2\)
\(\Leftrightarrow2x^2-3x+2x-3-3x+6=2\left(x^2-2x+1\right)\)
\(\Leftrightarrow2x^2-4x+3-2x^2+4x-2=0\)
\(\Leftrightarrow1=0\)(vô lý)
Vậy: \(S=\varnothing\)
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thực hiện phép tính
\(\dfrac{1}{3x-2}-\dfrac{1}{3x+2}-\dfrac{3x-6}{9x^2-4}\)
\(\dfrac{x+25}{2x^2-50}-\dfrac{x+5}{x^2-5x}-\dfrac{5-x}{2x^2+10x}\)
\(\dfrac{1-2x}{2x}-\dfrac{4x}{2x-1}-\dfrac{3}{2x-4x^2}\)
a) \(\dfrac{1}{3x-2}-\dfrac{1}{3x+2}-\dfrac{3x-6}{9x^2-4}\)
\(=\dfrac{3x+2-3x+2-3x+6}{\left(3x-2\right)\left(3x+2\right)}\)
\(=\dfrac{-3x+10}{\left(3x-2\right)\left(3x+2\right)}\)
b) \(\dfrac{x+25}{2x^2-50}-\dfrac{x+5}{x^2-5x}-\dfrac{5-x}{2x^2+10x}\)
\(=\dfrac{x+25}{2\left(x-5\right)\left(x+5\right)}-\dfrac{x+5}{x\left(x-5\right)}+\dfrac{x-5}{2x\left(x+5\right)}\)
\(=\dfrac{x^2+25x-2\left(x+5\right)^2+\left(x-5\right)^2}{2x\left(x-5\right)\left(x+5\right)}\)
\(=\dfrac{x^2+25x-2x^2-20x-50+x^2-10x+25}{2x\left(x-5\right)\left(x+5\right)}\)
\(=\dfrac{-5x-25}{2x\left(x-5\right)\left(x+5\right)}\)
\(=\dfrac{-5\left(x+5\right)}{2x\left(x-5\right)\left(x+5\right)}=\dfrac{-5}{2x\left(x-5\right)}\)
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c) Ta có: \(\dfrac{1-2x}{2x}-\dfrac{4x}{2x-1}-\dfrac{3}{2x-4x^2}\)
\(=\dfrac{-\left(2x-1\right)^2-8x^2+3}{2x\left(2x-1\right)}\)
\(=\dfrac{-\left(4x^2-4x+1\right)-8x^2+3}{2x\left(2x-1\right)}\)
\(=\dfrac{-4x^2+4x-1-8x^2+3}{2x\left(2x-1\right)}\)
\(=\dfrac{-12x^2+4x+2}{2x\left(2x-1\right)}\)
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18 tháng 2 2021 lúc 13:31
Câu 3 Thực hiện phép tính::(2 điểm )
a/ \(\dfrac{x^2}{x+2}\) + \(\dfrac{2x}{x+2}\)
b/ \(\dfrac{5x+4}{3x+15}\) - \(\dfrac{x-2}{x+5}\)
a) \(\dfrac{x^2+2x}{x+2}=\dfrac{x\left(x+2\right)}{x+2}=x\)
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b) \(\dfrac{5x+4-3\left(x-2\right)}{3\left(x+5\right)}=\dfrac{5x+4-3x+6}{3\left(x+5\right)}=\dfrac{2x+10}{3\left(x+5\right)}=\dfrac{2\left(x+5\right)}{3\left(x+5\right)}=\dfrac{2}{3}\)
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a) Ta có: \(\dfrac{x^2}{x+2}+\dfrac{2x}{x+2}\)
\(=\dfrac{x^2+2x}{x+2}\)
\(=\dfrac{x\left(x+2\right)}{x+2}=x\)
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1/ \(\dfrac{x-4}{3}+2x=\dfrac{4x-2}{6}\)
2/ \(\dfrac{5x-2}{5}-2=\dfrac{1-2x}{3}\)
3/ \(\dfrac{x-2}{2}-\dfrac{2}{3}=x-1\)
4/ \(\dfrac{2x-1}{3}+\dfrac{3x-2}{4}=\dfrac{4x-3}{5}\)
5/ \(\dfrac{x-3}{9}-\dfrac{x+2}{6}=\dfrac{x+4}{18}-\dfrac{1}{2}\)
1: Ta có: \(\dfrac{x-4}{3}+2x=\dfrac{4x-2}{6}\)
\(\Leftrightarrow2x-8+12x=4x-2\)
\(\Leftrightarrow10x=6\)
hay \(x=\dfrac{3}{5}\)
2: Ta có: \(\dfrac{5x-2}{5}-2=\dfrac{1-2x}{3}\)
\(\Leftrightarrow15x-6-30=10-20x\)
\(\Leftrightarrow35x=46\)
hay \(x=\dfrac{46}{35}\)
3: Ta có: \(\dfrac{x-2}{2}-\dfrac{2}{3}=x-1\)
\(\Leftrightarrow3x-6-4=6x-6\)
\(\Leftrightarrow-3x=4\)
hay \(x=-\dfrac{4}{3}\)
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1)\(\dfrac{x-4}{3}+2x=\dfrac{4x-2}{6}\)
\(\Leftrightarrow\dfrac{\left(x-4\right).2}{3.2}+\dfrac{2x.6}{6}=\dfrac{4x-2}{6}\)
\(\Rightarrow2x-8+12x=4x-2\\ \Leftrightarrow10x=6\\ \Leftrightarrow x=\dfrac{3}{5}\)
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4: Ta có: \(\dfrac{2x-1}{3}+\dfrac{3x-2}{4}=\dfrac{4x-3}{5}\)
\(\Leftrightarrow40x-20+45x-30=48x-36\)
\(\Leftrightarrow37x=14\)
hay \(x=\dfrac{14}{37}\)
5: Ta có: \(\dfrac{x-3}{9}-\dfrac{x+2}{6}=\dfrac{x+4}{18}-\dfrac{1}{2}\)
\(\Leftrightarrow2x-6-3x-6=x+4-9\)
\(\Leftrightarrow-x-x=-5-12=-17\)
hay \(x=\dfrac{17}{2}\)
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Tìm điều kiện có nghĩa:
1) \(\sqrt{x^2+2x-3}\)
2) \(\sqrt{2x^2+5x+3}\)
3) \(\sqrt{\dfrac{4}{x-1}}\)
4) \(\sqrt{\dfrac{-1}{x-3}}\)
5) \(\sqrt{\dfrac{-3}{x+2}}\)
6) \(\sqrt{\dfrac{1}{2a-1}}\)
LÀM CHI TIẾT GIÚP MK NHÉ!
1) ĐKXĐ: \(x^2+2x-3\ge0\Leftrightarrow\left(x+1\right)^2\ge4\)
\(\Leftrightarrow\left[{}\begin{matrix}x+1\ge2\\x+1\le-2\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x\ge1\\x\le-3\end{matrix}\right.\)
2) ĐKXĐ: \(2x^2+5x+3\ge0\Leftrightarrow2\left(x+\dfrac{5}{4}\right)^2\ge\dfrac{1}{8}\Leftrightarrow\left(x+\dfrac{5}{4}\right)^2\ge\dfrac{1}{16}\)
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{5}{4}\ge\dfrac{1}{4}\\x+\dfrac{5}{4}\le-\dfrac{1}{4}\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x\ge-1\\x\le-\dfrac{3}{2}\end{matrix}\right.\)
3) ĐKXĐ: \(x-1>0\Leftrightarrow x>1\)
4) ĐKXĐ: \(x-3< 0\Leftrightarrow x< 3\)
5) ĐKXĐ: \(x+2< 0\Leftrightarrow x< -2\)
6) ĐKXĐ: \(2a-1>0\Leftrightarrow a>\dfrac{1}{2}\)
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Giai các bpt sau
a,\(\dfrac{5x^2-3}{5}+\dfrac{3x-1}{4}< \dfrac{x\left(2x+3\right)}{2}-5\)
b,\(\dfrac{5x-2}{-3}\)\(-\dfrac{2x^2-x}{-2}>\dfrac{x\left(1-3x\right)}{-3}-\dfrac{5x}{-4}\)
a: \(\Leftrightarrow4\left(5x^2-3\right)+5\left(3x-1\right)< 10x\left(2x+3\right)-100\)
\(\Leftrightarrow20x^2-12x+15x-5< 20x^2+30x-100\)
=>3x-5<=30x-100
=>30x-100>3x-5
=>27x>95
hay x>95/27
b: \(\Leftrightarrow4\left(5x-2\right)-6\left(2x^2-x\right)< 4x\left(1-3x\right)-15x\)
\(\Leftrightarrow20x-8-12x^2+6x< 4x-12x^2-15x\)
=>26x-8<-11x
=>37x<8
hay x<8/37
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