Các bạn nhớ ghi cách làm ra nhé!

giải giúp mình mình cho k

mik hong bt làm:))

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 = \(\frac{-8}{25}\)

thanks

\(a.=415+58-415-38\)

\(=\left(415-415\right)+\left(58-38\right)\)

\(=0+30\)

\(=30\)

cám ơn

1: \(5\cdot25\cdot2\cdot16\cdot4=10\cdot25\cdot4\cdot16=10\cdot100\cdot16=16000\)

2: \(25\cdot5\cdot4\cdot2\cdot27\)

\(=25\cdot4\cdot5\cdot2\cdot27\)

\(=100\cdot10\cdot27=27000\)

3: \(2^3\cdot17-2^3\cdot17=2^3\left(17-17\right)=0\)

4: \(58\cdot75+58\cdot50-58\cdot25\)

\(=58\left(75+50-25\right)\)

\(=58\cdot100=5800\)

7: \(5\cdot23+35\cdot41+64\cdot65\)

\(=5\left(23+7\cdot41\right)+64\cdot65\)

\(=5\cdot310+64\cdot65=1550+4160=5710\)