a,b,c>0 thỏa mãn x+y+z=4. cũng chứng minh 1/xy+1/xz
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Bài 5: Phương trình chứa ẩn ở mẫu
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Bài 1:a, dfrac{x}{x-1}-dfrac{2x}{x^2-1}0
b, dfrac{left(x+2right)^2}{2x-3}-1dfrac{x^2+10}{2x-3}
c,dfrac{x+5}{x-5}-dfrac{x-5}{x+5}dfrac{20}{x^2-25}
d,dfrac{3x+2}{3x-2}-dfrac{6}{2+3x}dfrac{9x^2}{9x^2-4}
e,dfrac{3}{5x-1}+dfrac{2}{3-5x}dfrac{4}{left(1-5xright)left(5x-3right)}
f,dfrac{3}{1-4x}dfrac{2}{4x+1}-dfrac{8+6x}{16x^2-1}
g,dfrac{y-1}{y-2}-dfrac{5}{y+2}dfrac{12}{y^2-4}+1
h,dfrac{x+1}{x-1}-dfrac{x-1}{x+1}dfrac{4}{x^2-1}
i,dfrac{2x-3}{x+2}-dfra...
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Help me... Giup đk chừng nào hay chừng đó ạ.
Bài 1:a, \(\dfrac{x}{x-1}-\dfrac{2x}{x^2-1}=0\)
b, \(\dfrac{\left(x+2\right)^2}{2x-3}-1=\dfrac{x^2+10}{2x-3}\)
c,\(\dfrac{x+5}{x-5}-\dfrac{x-5}{x+5}=\dfrac{20}{x^2-25}\)
d,\(\dfrac{3x+2}{3x-2}-\dfrac{6}{2+3x}=\dfrac{9x^2}{9x^2-4}\)
e,\(\dfrac{3}{5x-1}+\dfrac{2}{3-5x}=\dfrac{4}{\left(1-5x\right)\left(5x-3\right)}\)
f,\(\dfrac{3}{1-4x}=\dfrac{2}{4x+1}-\dfrac{8+6x}{16x^2-1}\)
g,\(\dfrac{y-1}{y-2}-\dfrac{5}{y+2}=\dfrac{12}{y^2-4}+1\)
h,\(\dfrac{x+1}{x-1}-\dfrac{x-1}{x+1}=\dfrac{4}{x^2-1}\)
i,\(\dfrac{2x-3}{x+2}-\dfrac{x+2}{x-2}=\dfrac{2}{x^2-4}\)
j,\(\dfrac{x-1}{x^2-4}=\dfrac{3}{2-x}\)
\(a.\dfrac{y-1}{y-2}-\dfrac{5}{y+2}=\dfrac{12}{y^2-4}+1\)
\(b.\dfrac{1}{x-1}-\dfrac{3x^2}{x^3-1}=\dfrac{2x}{x^2+x+1}\)
5.c) \(\dfrac{x+1}{x^2+x+1}-\dfrac{x-1}{x^2-x-1}=\dfrac{3}{x\left(x^4+x^2+1\right)}\)
6.b) \(\dfrac{4}{2x^3+3x^2-8x-12}-\dfrac{1}{x^2-4}-\dfrac{4}{2x^2+7x+6}+\dfrac{1}{2x+3}=0\)
Bài 2:giải các pt chứa ẩn ở mẫu sau:
a)\(\dfrac{x+1}{x-1}-\dfrac{x-1}{x+1}=\dfrac{16}{x^2-1}\)
b)\(\dfrac{12}{x^2-4}-\dfrac{x+1}{x-2}+\dfrac{x+7}{x+2}=0\)
c)\(\dfrac{12}{8+x^3}=1+\dfrac{1}{x+2}\)
d)\(\dfrac{x+25}{2x^2-50}-\dfrac{x+5}{x^2-5x}=\dfrac{5-x}{2x^2+10x}\)
\(a,\dfrac{3\left(2x+1\right)}{4}-5-\dfrac{3x+2}{10}=\dfrac{2\left(3x-1\right)}{5}\)
b,\(\dfrac{x-15}{23}+\dfrac{x-23}{15}-2=0\)
c,\(\dfrac{3\left(2x+1\right)}{4}-\dfrac{5x+3}{6}+\dfrac{x+1}{3}=x+\dfrac{7}{12}\)
Giải các phương trình sau:
a) \(\dfrac{1}{4z^{2}-12z+9}-\dfrac{3}{9-4z^{2}}=\dfrac{4}{4z^{2}+12z+9}\)
b) \(\dfrac{2}{(1-3u)(3u+11)}=\dfrac{1}{9u^{2}-6u+1}-\dfrac{3}{(3u+11)^{2}}\)
c) \(\dfrac{4}{2x^{3}+3x^{2}-8x-12}-\dfrac{1}{x^{2}-4}-\dfrac{4}{2x^{2}+7x+6}+\dfrac{1}{2x+3}=0\)
giải phương trình sau:
a) \(\dfrac{8}{x-8}+\dfrac{11}{x-11}=\dfrac{9}{x-9}+\dfrac{10}{x-10}\)
b) \(\dfrac{x}{x-3}-\dfrac{x}{x-5}=\dfrac{x}{x-4}-\dfrac{x}{x-6}\)
c) \(\dfrac{4}{x^2-3x+2}-\dfrac{3}{2x^2-6x+1}+1=0\)
d) \(\dfrac{1}{x-1}+\dfrac{2}{x-2}+\dfrac{3}{x-3}=\dfrac{6}{x-6}\)
6 tháng 4 2020 lúc 8:18
Cho 2 số x,y dương
Chứng minh rằng \(\frac{1}{x}\)+\(\frac{1}{y}\)≥\(\frac{4}{x+y}\)
Tìm giá trị nhỏ nhất của biểu thức \(\frac{1}{xy}\)+\(\frac{1}{x^2+xy}\)+\(\frac{1}{y^2+xy}\)+\(\frac{1}{x^2+y^2}\) với x+y≤1
Giải các pt với tham số là a,b,c
a , dfrac{x-a}{3}dfrac{x+3}{a}-2 e, 3x+dfrac{x}{a}-dfrac{3a}{a+1}dfrac{4ax}{left(a+1right)^2}+dfrac{left(2a+1right)x}{aleft(a+1right)^2}-dfrac{3a^2}{left(a+1right)^3}
b, dfrac{x-a}{a+1}+dfrac{x-1}{a-1}dfrac{2a}{1-a^2}
c, dfrac{x+a-1}{a+2}+dfrac{x-a}{a-2}+dfrac{x-a}{4-a^2}
d, dfrac{x-a}{b+c}+dfrac{x-b}{c+a}+dfrac{x-c}{a+b}3
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Giải các pt với tham số là a,b,c
a , \(\dfrac{x-a}{3}=\dfrac{x+3}{a}-2\) e, \(3x+\dfrac{x}{a}-\dfrac{3a}{a+1}=\dfrac{4ax}{\left(a+1\right)^2}+\dfrac{\left(2a+1\right)x}{a\left(a+1\right)^2}-\dfrac{3a^2}{\left(a+1\right)^3}\)
b, \(\dfrac{x-a}{a+1}+\dfrac{x-1}{a-1}=\dfrac{2a}{1-a^2}\)
c, \(\dfrac{x+a-1}{a+2}+\dfrac{x-a}{a-2}+\dfrac{x-a}{4-a^2}\)
d, \(\dfrac{x-a}{b+c}+\dfrac{x-b}{c+a}+\dfrac{x-c}{a+b}=3\)