Tìm x , biết:
x/3 = 5/6 + (-1)/3
Cc giúp mk vs nhen:>>Mk sẽ tick cho
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\(\frac{x}{5}=\frac{y}{3}\)và x2-y2=4(x,y>0)
\(\Rightarrow\frac{x}{5}=\frac{y}{3}=\frac{x^2}{5^2}=\frac{y^2}{3^2}=\frac{x^2-y^2}{25-9}=\frac{4}{16}=\frac{1}{4}\)
Áp dụng tính chất của dãy tỉ số bằng nhau , ta có :
\(\Rightarrow\frac{x^2}{25}=\frac{1}{4}\Rightarrow x^2=\frac{25}{4}\Rightarrow x=\frac{5}{2}\)
\(\Rightarrow\frac{y^2}{9}=\frac{1}{4}\Rightarrow y^2=\frac{9}{4}\Rightarrow y=\frac{3}{2}\)
Vậy x =\(\frac{5}{2}\)và y =\(\frac{3}{2}\)
Ta có:
\(\frac{x}{3}=\frac{y}{5}\Rightarrow\frac{x^2}{3}=\frac{y^2}{5}\)
Áp dụng dãy tỉ số bằng nhau, ta có:
\(\frac{x^2}{3^2}=\frac{y^2}{5^2}=\frac{x^2-y^2}{3^2-5^2}=\frac{-4}{-16}=\frac{1}{4}\)
\(\Rightarrow\frac{x^2}{3^2}=\frac{1}{4}\Rightarrow x=\sqrt{3^2.\frac{1}{4}}=\frac{3}{2}\)
\(\frac{y^2}{5^2}=\frac{1}{4}\Rightarrow y=\sqrt{5^2.\frac{1}{4}}=\frac{5}{2}\)
a) 5x.(x+3/4) = 0
=> x = 0
x+3/4 = 0 => x = -3/4
b) \(\frac{x+7}{2010}+\frac{x+6}{2011}=\frac{x+5}{2012}+\frac{x+4}{2013}.\)
\(\Rightarrow\frac{x+7}{2010}+\frac{x+6}{2011}-\frac{x+5}{2012}-\frac{x+4}{2013}=0\)
\(\frac{x+7}{2010}+1+\frac{x+6}{2011}+1-\frac{x+5}{2012}-1-\frac{x+4}{2013}-1=0\)
\(\left(\frac{x+7}{2010}+1\right)+\left(\frac{x+6}{2011}+1\right)-\left(\frac{x+5}{2012}+1\right)-\left(\frac{x+4}{2013}+1\right)=0\)
\(\frac{x+2017}{2010}+\frac{x+2017}{2011}-\frac{x+2017}{2012}-\frac{x+2017}{2013}=0\)
\(\left(x+2017\right).\left(\frac{1}{2010}+\frac{1}{2011}-\frac{1}{2012}-\frac{1}{2013}\right)=0\)
=> x + 2017 = 0
x = -2017
a) để 2x - 3 > 0
=> 2x > 3
x > 3/2
b) 13-5x < 0
=> 5x < 13
x < 13/5
c) \(\frac{x+3}{2x-1}>0\)
=> x + 3 > 0
x > -3
d) \(\frac{x+7}{x+3}=\frac{x+3+4}{x+3}=1+\frac{4}{x+3}\)
Để x+7/x+3 < 1
=> 1 + 4/x+3 < 1
=> 4/x+3 < 0
=> không tìm được x thỏa mãn điều kiện
A)\(\left|x-2\right|< 7\Rightarrow\left|x-2\right|\in\left\{0;1;2;3;4;5;6\right\}\)
\(\Rightarrow\left(x-2\right)\in\left\{-6;-5;-4;-3;-2;-1;0;1;2;3;4;5;6\right\}\)
\(\Rightarrow x\in\left\{-4;-3;-2;-1;0;1;2;3;4;5;6;7;8\right\}\)
B) \(\left|5+x\right|>4\Rightarrow\left|5+x\right|\in\left\{5;6;7;8;9;...\right\}\)
\(\Rightarrow\left(5+x\right)\in\left\{...;-7;-6;-5;5;6;7;8;...\right\}\)
\(\Rightarrow x\in\left\{...;-5;-4;-3;-2;-1;0;1;2;3;4;5;...\right\}\)
Để \(A=\frac{5}{x-2014}\)đạt giá trị nguyên
\(\Rightarrow x-2014\inƯ\left(5\right)=\left\{\pm1;\pm5\right\}\)
\(x-2014=1\Rightarrow x=2015\)
\(x-2014=-1\Leftrightarrow x=2013\)
\(x-2014=5\Rightarrow x=2019\)
\(x-2014=-5\Rightarrow x=2009\)
\(KL:x\in\left\{2015;2013;2009;2019\right\}\)
\(\frac{x}{3}\)=\(\frac{5}{6}\)-\(\frac{1}{3}\)<=>\(\frac{x}{3}\)=\(\frac{1}{2}\)<=>x=\(\frac{3}{2}\)