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a: \(\Leftrightarrow x\cdot12.3=123\)
=>x=10
b: \(\dfrac{3x-0.8}{x}+14.5=15\)
\(\Leftrightarrow\dfrac{3x-0.8}{x}=0.5\)
\(\Leftrightarrow3x-0.8=0.5x\)
=>2,5x=0,8
hay x=8/25
c: \(\Leftrightarrow12.5\cdot x=5.58-4.85=0.73\)
hay x=73/1250
1 (3y - 0,8 ) : y + 14,5 = 15
( 3y - 0,8 ) : y = 0,5
3y : y - 0,8 : y = 0,5
3 - 0,8 : y = 0,5
0,8 : y = 2,5
y = 0,8 : 2,5
y = 0,32
Ta có :
Tử số = 2012 x 14 + 1997 + 2010 x 2011
= ( 2011 + 1 ) x 14 + 1997 + 2010 x 2011
= 2011 x 14 + 1 x 14 + 1997 + 2010 x 2011
= 2011 x 14 + 14 + 1997 + 2010 x 2011
= ( 2011 x 14 ) + ( 14 + 1997 ) + ( 2010 x 2011 )
= 2011 x 14 + 2011 + 2010 x 2011
= 2011 x ( 14 + 1 + 2010 )
= 2011 x 2025
Mẫu số = 2011 x 5 + 2011 x 1008 + 1012 x 2011
= 2011 x ( 5 + 1008 + 1012 )
= 2011 x 2025
=> \(A=\frac{2011\times2025}{2011\times2025}=1\)
1: =>x:7/3=-3/2
hay \(x=-\dfrac{3}{2}\cdot\dfrac{7}{3}=-\dfrac{7}{2}\)
2: \(x=\dfrac{11}{15}:\dfrac{2}{5}=\dfrac{11}{15}\cdot\dfrac{5}{2}=\dfrac{55}{30}=\dfrac{11}{6}\)
3: \(x=-\dfrac{6}{5}:\dfrac{3}{10}=\dfrac{-6}{5}\cdot\dfrac{10}{3}=\dfrac{-60}{15}=-4\)
4: \(x=\dfrac{1}{3}+\dfrac{3}{20}=\dfrac{20+9}{60}=\dfrac{29}{60}\)
6: \(\Leftrightarrow x\cdot\dfrac{13}{20}=\dfrac{5}{4}\)
hay \(x=\dfrac{5}{4}:\dfrac{13}{20}=\dfrac{5}{4}\cdot\dfrac{20}{13}=\dfrac{100}{52}=\dfrac{25}{13}\)
\(11\left(x-6\right)=4x+11\)
\(\Rightarrow11x-66=4x+11\)
\(\Rightarrow11x-4x=66+11\)
\(\Rightarrow7x=77\)
\(\Rightarrow x=11\)
Vậy x = 11
\(\left(3x+0,8\right)\div x+14,5=15\)
\(\Rightarrow\left(3x+0,8\right)\div x=15-14,5\)
\(\Rightarrow\left(3x+0,8\right)\div x=0,5\)
\(\Rightarrow3x+0,8=0,5x\)
\(\Rightarrow-2,5x=0,8\)
\(\Rightarrow x=0,8\div\left(-2,5\right)=\frac{-8}{25}\)
Vậy x = \(\frac{-8}{25}\)
\(a.=415+58-415-38\)
\(=\left(415-415\right)+\left(58-38\right)\)
\(=0+30\)
\(=30\)
\(1,2\cdot35+2,56:0,8+58\\ =42+3,2+58\\ =103,2\\ \\ \left(23+15:2,5\right):14,5+17\\ =\left(23+6\right):14,5+17\\ =29:14,5+17=2+17\\ =19\)
\(1,2.3,5+2,56:0,8+58=4,2+3,2+58=7,4+58=65,4\)