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TP
0
26 tháng 3 2017
Ta có:
\(60\%X+\dfrac{2}{3}=\dfrac{1}{3}.6+\dfrac{1}{3}\\ < =>60\%X=\dfrac{1}{3}.6+\dfrac{1}{3}-\dfrac{2}{3}\\ < =>60\%X=2+\dfrac{1}{3}-\dfrac{2}{3}\\ < =>60\%X=\dfrac{5}{3}\\ =>X=\dfrac{5}{3}:60\%=\dfrac{25}{9}\)
Vậy: X có giá trị bằng 25/9
8 tháng 5 2019
a) \(60\%x+\frac{2}{3}x=\frac{1}{3}.6\frac{1}{3}\)
=> \(\frac{3}{5}x+\frac{2}{3}x=\frac{19}{9}\)
=> \(\frac{19}{15}x=\frac{19}{9}\)
=> \(x=\frac{19}{9}:\frac{19}{15}\)
=> \(x=\frac{5}{3}\)
b) (-0,6x - 1/3) . 3/5 - (-1) = 1/3
=> (-3/5x - 1/3) .3/5 = 1/3 - 1
=> (-3/5x - 1/3).3/5 = -2/3
=> -3/5x - 1/3 = -2/3 : 3/5
=> -3/5x - 1/3 = -10/9
=> -3/5x = -10/9 + 1/3
=> -3/5x = -7/9
=> x = -7/9 : (-3/5)
=> x = 35/27
8 tháng 5 2019
a,60%x+2/3x=1/3.6 1/3
x(60%+2/3)=19/6
x.19/15=19/6
x=19/6 : 19/15
x=5/2
b,[-0,6x-1/2].3/4-(-1)=1/3
(-3/5x-1/2).3/4=1/3-1
(-3/5x-1/2).3/4=-2/3
-0,6x-0,5=-2/3:3/4
................................
c,2[1/2x-1/3]-3/2=1/4
....................................... (tương tự...)
d,Số đó là:720% : 2/3=10,8
KN
23 tháng 4 2019
\(-5\left(x+\frac{1}{5}\right)-\frac{1}{2}\left(x-\frac{2}{3}\right)=\frac{3}{2}x-\frac{5}{6}\)
\(\Leftrightarrow-5x-\frac{1}{5}-\frac{1}{2}x+\frac{1}{3}=\frac{3}{2}x-\frac{5}{6}\)
\(\Leftrightarrow\left(-5x-\frac{1}{2}x\right)+\left(\frac{1}{3}-\frac{1}{5}\right)=\frac{3}{2}x-\frac{5}{6}\)
\(\Leftrightarrow\left(\frac{-10}{2}x-\frac{1}{2}x\right)+\left(\frac{5}{15}-\frac{3}{15}\right)=\frac{3}{2}x-\frac{5}{6}\)
\(\Leftrightarrow\frac{-11}{2}x+\frac{2}{15}=\frac{3}{2}x-\frac{5}{6}\)
\(\Leftrightarrow\frac{-11}{2}x-\frac{3}{2}x=-\frac{5}{6}-\frac{2}{15}\)
\(\Leftrightarrow\frac{-14}{2}x=-\frac{25}{30}-\frac{4}{30}\)
\(\Leftrightarrow-7x=-\frac{29}{30}\)
\(\Leftrightarrow x=-\frac{29}{30}\times\frac{-1}{7}\)
\(\Leftrightarrow x=\frac{29}{210}\)
KN
23 tháng 4 2019
\(3\left(x-\frac{1}{2}\right)-5\left(x+\frac{3}{5}\right)=-x+\frac{1}{5}\)
\(\Leftrightarrow3x-\frac{3}{2}-5x-3=\frac{1}{5}-x\)
\(\Leftrightarrow\left(3x-5x\right)-\left(\frac{3}{2}+3\right)=\frac{1}{5}-x\)
\(\Leftrightarrow-2x-\left(\frac{3}{2}+\frac{6}{2}\right)=\frac{1}{5}-x\)
\(\Leftrightarrow-2x-\frac{9}{2}=\frac{1}{5}-x\)
\(\Leftrightarrow-2x+x=\frac{1}{5}+\frac{9}{2}\)
\(\Leftrightarrow-x=\frac{2}{10}+\frac{45}{10}\)
\(\Leftrightarrow-x=\frac{47}{10}\)
\(\Leftrightarrow x=\frac{-47}{10}\)
H9
HT.Phong (9A5)
CTVHS
9 tháng 7 2023
a) Đặt: \(A=1+2^2+2^3+...+2^{10}\)
\(\Rightarrow2A=2\left(1+2^2+2^3+...+2^9+2^{10}\right)\)
\(\Rightarrow2A=2+2^3+2^4+...+2^{10}+2^{11}\)
\(\Rightarrow2A-A=\left(2+2^3+2^4+...+2^{10}+2^{11}\right)-\left(1+2^2+2^3+...+2^{10}\right)\)
\(\Rightarrow A=\left(2^3-2^3\right)+\left(2^4-2^4\right)+...+\left(2-1\right)+\left(2^{11}-2^2\right)\)
\(\Rightarrow A=0+0+...+1+\left(2^{11}-2^2\right)\)
\(\Rightarrow A=1+2^{11}-2^2=1+2048-4=2045\)
Vậy: \(1+2^2+2^3+...+2^{10}=2045\)
b)
a] \(60-3\left(x-1\right)=2^3\cdot3\)
\(\Rightarrow60-3\left(x-1\right)=24\)
\(\Rightarrow3\left(x-1\right)=36\)
\(\Rightarrow x-1=12\)
\(\Rightarrow x=13\)
b] \(\left(3x-2\right)^3=2\cdot2^5\)
\(\Rightarrow\left(3x-2\right)^3=2^6\)
\(\Rightarrow\left(3x-2\right)^3=\left(2^2\right)^3\)
\(\Rightarrow3x-2=2^2\)
\(\Rightarrow3x=6\)
\(x=2\)
c] \(5^{x+1}-5^x=500\)
\(\Rightarrow5^x\left(5-1\right)=500\)
\(\Rightarrow5^x\cdot4=500\)
\(\Rightarrow5^x=125\)
\(\Rightarrow5^x=5^3\)
\(\Rightarrow x=3\)
d] \(x^2=x^4\)
\(\Rightarrow x=x^2\)
\(\Rightarrow x-x^2=0\)
\(\Rightarrow x\left(1-x\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\1-x=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)