tìm x : 3^2*x =28
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\(1,\sqrt{3}x-3=\sqrt{27}\)
\(\Leftrightarrow\sqrt{3}x-3=3\sqrt{3}\)
\(\Leftrightarrow\sqrt{3}\left(x-\sqrt{3}\right)=3\sqrt{3}\)
\(\Leftrightarrow x-\sqrt{3}=3\)
\(\Leftrightarrow x=3+\sqrt{3}\)
\(2,\sqrt{2}x-\sqrt{28}=\sqrt{32}\)
\(\Leftrightarrow\sqrt{2}x-2\sqrt{7}=4\sqrt{2}\)
\(\Leftrightarrow\sqrt{2}x=4\sqrt{2}+2\sqrt{7}\)
\(\Leftrightarrow x=\dfrac{\sqrt{2^2}\left(2\sqrt{2}+\sqrt{7}\right)}{\sqrt{2}}\)
\(\Leftrightarrow x=\sqrt{2}\left(2\sqrt{2}+\sqrt{7}\right)\)
\(\Leftrightarrow x=4+\sqrt{14}\)
\(3,\sqrt{6}x-2\sqrt{6}=\sqrt{54}\)
\(\Leftrightarrow\sqrt{6}\left(x-2\right)=3\sqrt{6}\)
\(\Leftrightarrow x-2=3\)
\(\Leftrightarrow x=5\)
\(4,\sqrt{3}x-\sqrt{2}x=\sqrt{3}+\sqrt{2}\)
\(\Leftrightarrow\left(\sqrt{3}-\sqrt{2}\right)x=\sqrt{3}+\sqrt{2}\)
\(\Leftrightarrow x=\dfrac{\sqrt{3}+\sqrt{2}}{\sqrt{3}-\sqrt{2}}\)
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\(a,\Rightarrow2\left(x+5\right)-12=-20\\ \Rightarrow2\left(x+5\right)=-8\\ \Rightarrow x+5=-4\Rightarrow x=-9\\ b,\Rightarrow x-28+x=-24\\ \Rightarrow2x=4\Rightarrow x=2\\ c,\Rightarrow6\left(x-2\right)^3=-384\\ \Rightarrow\left(x-2\right)^3=-64=\left(-4\right)^3\\ \Rightarrow x-2=-4\Rightarrow x=-2\\ d,\Rightarrow2^x\left(1+2^3\right)=72\\ \Rightarrow2^x\cdot9=72\\ \Rightarrow2^x=8=2^3\Rightarrow x=3\)
a,⇒2(x+5)−12=−20⇒2(x+5)=−8⇒x+5=−4⇒x=−9b,⇒x−28+x=−24⇒2x=4⇒x=2c,⇒6(x−2)3=−384⇒(x−2)3=−64=(−4)3⇒x−2=−4⇒x=−2d,⇒2x(1+23)=72⇒2x⋅9=72⇒2x=8=23⇒x=3a,⇒2(x+5)−12=−20⇒2(x+5)=−8⇒x+5=−4⇒x=−9b,⇒x−28+x=−24⇒2x=4⇒x=2c,⇒6(x−2)3=−384⇒(x−2)3=−64=(−4)3⇒x−2=−4⇒x=−2d,⇒2x(1+23)=72⇒2x⋅9=72⇒2x=8=23⇒x=3
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\(2x+3=15\\ \Rightarrow2x=15-3=12\\ \Rightarrow x=\dfrac{12}{2}=6\\ ---\\ 28-3x=13\\ \Rightarrow3x=28-13=15\\ \Rightarrow x=\dfrac{15}{3}=5\\ ---\\ \left(x-1954\right).5=50\\ \Rightarrow x-1954=50:5=10\\ \Rightarrow x=10+1954=1964\\ ---\\ x-152:2=46\\ \Rightarrow x-76=46\\ \Rightarrow x=46+76=122\)
a, 2\(x\) + 3 = 15
2\(x\) = 12
\(x\) = 6
b, 28 - 3\(x\) = 13
3\(x\) = 28 - 13
3\(x\) = 15
\(x\) = 5
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Tìm x:
\(a.\dfrac{35}{28}-x=\dfrac{5}{14}\\ x=\dfrac{35}{28}-\dfrac{5}{14}\\ x=\dfrac{25}{28}\\ b.\dfrac{6}{7}\times x=\dfrac{2}{3}\\ x=\dfrac{2}{3}:\dfrac{6}{7}\\ x=\dfrac{7}{9}\\ c.x\times7=\dfrac{3}{4}\\ x=\dfrac{3}{4}:7\\ x=\dfrac{3}{28}\\ d.2:x-\dfrac{1}{3}=\dfrac{2}{5}\\ 2:x=\dfrac{2}{5}+\dfrac{1}{3}\\ 2:x=\dfrac{11}{15}\\ x=2:\dfrac{11}{15}\\ x=\dfrac{30}{11}.\)
\(a,\dfrac{35}{28}-x=\dfrac{5}{14}\)
\(x=\dfrac{35}{28}-\dfrac{5}{14}\)
\(x=\dfrac{25}{28}\)
\(b,\dfrac{6}{7}\times x=\dfrac{2}{3}\)
\(x=\dfrac{2}{3}:\dfrac{6}{7}\)
\(x=\dfrac{7}{9}\)
\(c,x\times7=\dfrac{3}{4}\)
\(x=\dfrac{3}{4}:7\)
\(x=\dfrac{3}{28}\)
\(d,2:x-\dfrac{1}{3}=\dfrac{2}{5}\)
\(2:x=\dfrac{2}{5}+\dfrac{1}{3}\)
\(2:x=\dfrac{11}{15}\)
\(x=2:\dfrac{11}{15}\)
\(x=\dfrac{30}{11}\)
#YVA
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a) Ta có : ( x + 1 ).( 3 - x ) > 0
Th1 : \(\hept{\begin{cases}x+1>0\\3-x>0\end{cases}\Rightarrow\hept{\begin{cases}x>-1\\x>3\end{cases}\Rightarrow}x>3}\)
Th2 : \(\hept{\begin{cases}x+1< 0\\3-x< 0\end{cases}\Rightarrow\hept{\begin{cases}x< -1\\x< 3\end{cases}\Rightarrow}x< -1}\)
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3^2.x=28
=> 9.x=28
=> x= 28:9
=> x=28/9
28/9 nha