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1.
a) \(\frac{13}{8}:\frac{13}{4}=\frac{1}{2}=0,5=50\%\)
b) \(12,5:2,5=5=500\%\)
~ Hok tốt ~
2.
\(\left(\frac{37}{9}+\frac{13}{4}\right).\frac{9}{4}+\frac{11}{4}\)
\(=\frac{265}{36}.\frac{9}{4}+\frac{11}{4}\)
\(=\frac{265}{16}+\frac{11}{4}\)
\(=\frac{309}{16}\)
\(1+\left(\frac{9}{10}-\frac{4}{5}\right):\frac{19}{6}\)
\(=1+\frac{1}{10}:\frac{19}{6}\)
\(=1+\frac{3}{95}\)
\(=\frac{98}{95}\)
\(\left(-7+\left|13\right|\right)-\left(13-\left|-7\right|-25\right)-\left(25+\left|-10\right|-9\right)\)
\(=\left(-7+13\right)-\left(13-7-25\right)-\left(25+10-9\right)\)
\(=-7+13-13+7+25-25-10+9\)
\(=\left(-7+7\right)+\left(13-13\right)+\left(25-25\right)-10+9\)
\(=0+0+0-10+9\)
\(=-10+9\)
\(=-1\)
~ Hok tốt ~
a: \(\Leftrightarrow x\cdot\dfrac{1}{2}=\dfrac{1}{4}\cdot\dfrac{-7}{2}+\dfrac{5}{3}=\dfrac{19}{24}\)
hay x=19/12
b: \(\Leftrightarrow\left(\dfrac{45}{11}-3x\right)\cdot\dfrac{11}{5}=\dfrac{21}{5}\)
\(\Leftrightarrow-3x+\dfrac{45}{11}=\dfrac{21}{11}\)
=>-3x=-24/11
=>x=8/11
c: \(\Leftrightarrow\left[{}\begin{matrix}3x-1=0\\5-\dfrac{1}{2}x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=10\end{matrix}\right.\)
d: \(\Leftrightarrow\left(2x+\dfrac{3}{5}\right)^2=\dfrac{16}{25}\)
\(\Leftrightarrow\left[{}\begin{matrix}2x+\dfrac{3}{5}=\dfrac{4}{5}\\2x+\dfrac{3}{5}=-\dfrac{4}{5}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{10}\\x=-\dfrac{7}{10}\end{matrix}\right.\)
a) x+30%x=-1.31
=> 100%x+30%x=-1.31
=>x.(100%+30%)=-1.31
=>x.13/10=-1.31=-1.31:13/10=-131/130
b) (x-1/2):1/3+5/7=9+5/7
=>(x-1/2).3+5/7=68/7
=>(x-1/2).3=68/7-5/7=9
=>x-1/2=9:3=3
=>x=3+1/2=3 1/2( hỗn số)
c) 1/2x-3/4=14/9.3/7
=>1/2x-3/4=2/3
=>1/2x=2/3+3/4=17/12
x=17/12:1/2=17/12.2=17/6
d) - 5/6 -x = 7/12+ -1/3
=>- 5/6 -x = 7/12+ -4/12=1/4
=> x = -5/6 -1/4=-13/12
e) x + 3/-15 = 1/3
=> x= 1/3 - -3/15 =1/3+3/15
=> x=5/15 + 3/15=8/15
f) (4,5 -2 x). (-1 4/7)=11/14
=> 4,5 -2x=11/14 : -3/7=11/14. -7/3=-11/6
=>-2x=-11/6-9/2= -11/6 -27/6 =-19/3
=>x= -19/3: -2x=19/6
Chúc bn thi HKII tốt!!!
a; -2\(x\) - 3.(\(x-17\)) = 34 - 2.( - \(x\) + 25)
- 2\(x\) - 3\(x\) + 51 = 34 + 2\(x\) - 50
2\(x\) + 2\(x\) + 3\(x\) = - 34 + 50 + 51
7\(x\) = 67
\(x\) = 67 : 7
\(x\) = \(\dfrac{67}{7}\)
Vậy \(x\) = \(\dfrac{67}{7}\)
b; 17\(x\) + 3.(- 16\(x\) - 37) = 2\(x\) + 43 - 4\(x\)
17\(x\) - 48\(x\) - 111 = 2\(x\) - 4\(x\) + 43
- 31\(x\) - 2\(x\) + 4\(x\) = 111 + 43
- \(x\) x (31 + 2 - 4) = 154
- \(x\) x (33 - 4) = 154
- \(x\) x 29 = 154
- \(x\) = 154 : (-29)
\(x\) = - \(\dfrac{154}{29}\)
Vậy \(x=-\dfrac{154}{29}\)