a, 2.(4x-3)-3(x+5)+4(x-10)=5(x+2)

    2.4x-2.3-3.x+3.5+4x-4.10=5x+5.2

    8x-6-3x+15+4x-40=5x-10

    8x-3x+4x-5x-6-15-40-10=0

    4x-71=0

    4x=71

     x=71:4

    x=71/4

x + 5/2 . x - 3/2 = 9/4

<=> x( 1+ 5/2 ) - 3/2 = 9/4

<=> x . 7/2      = 9/4 + 3/2

<=>   x .7/2     = 15/4

<=>  x              = 15/4 : 7/2

<=>    x            = 15/14

TA CÓ: 

X + 5/2 . X - 3/2 = 9/4

X + 5/2 .X = 9/4 +3/2 = 15/4 

(X . 1) + (5/2 . X) = 15/4

X . (1 + 5/2) =15/4

X . 7/2 = 15/4

X = (15/4) / (7/2)

X = 15/14

DỄ ÒM MÀ

BẠN HỌC TRỪNG NÀO MÀ MAI NỘP VẬY

mk hc thêm bn DTC CAO THU ơi

Ta có x(y-2)= 3.1=1.3=-1. -3= -3. -1

Xét từng trường hợp

TH1: x=3

          y-2=1 => y=3

TH2 x=1

       y-2=3 => y=5

Bạn làm tiếp với các Th tiếp theo nhé

\(\dfrac{-5}{3}-\left(\dfrac{5}{12}-\dfrac{3}{4}\right)< x< \dfrac{11}{6}-\left(\dfrac{1}{3}+\dfrac{1}{4}\right)\)

\(\Rightarrow\left\{{}\begin{matrix}x>\dfrac{-5}{3}-\left(\dfrac{5}{12}-\dfrac{3}{4}\right)\\x< \dfrac{11}{6}-\left(\dfrac{1}{3}+\dfrac{1}{4}\right)\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}x>\dfrac{-5}{3}-\dfrac{5}{12}+\dfrac{3}{4}\\x< \dfrac{11}{6}-\dfrac{1}{3}-\dfrac{1}{4}\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}x>\dfrac{-20}{12}-\dfrac{5}{12}+\dfrac{9}{12}\\x< \dfrac{22}{12}-\dfrac{4}{12}-\dfrac{3}{12}\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}x>-\dfrac{4}{3}\\x< \dfrac{5}{4}\end{matrix}\right.\Rightarrow x\in\left\{-\dfrac{4}{3};\dfrac{5}{4}\right\}}\)

mai cậu đi học à

 \(\left|x-2\right|+\left|x-3\right|+\left|x-4\right|=2\)

\(\le\left|x\right|-\left|2\right|+\left|x\right|-\left|3\right|+\left|x\right|-\left|4\right|\)

\(x-2+x-3+x-4=2\)

\(\Leftrightarrow x+x+x-2-3-4=2\)

\(\Leftrightarrow x^3-2-3-4=2\)

\(x^3=2+4+3+2\)

\(x^3=11\)

\(x=\sqrt[3]{11}\)

Ta có: A=(1-1/2)...........................

Mà các tử có hiệu bằng 0

suy ra: Phân số có tử bằng 0

suy ra: A=0

Vậy A=0

Tích cho mk nha bn

Ta co: (1-1/2)* (1-1/3)*(1-1/4)*........*(1-1/2016)

=1/2*2/3*3/4*.....*2015/2016

=1*2*3*.....*2015/2*3*4*.....*2016

=1/2016

a: \(A=\dfrac{5}{4}\cdot\dfrac{11}{3}\cdot\dfrac{-1}{11}=\dfrac{-5}{12}=\dfrac{-25}{60}=\dfrac{-50}{120}\)

b: \(B=\dfrac{3}{4}\cdot\dfrac{1}{12}\cdot\dfrac{2}{3}=\dfrac{1}{24}=\dfrac{5}{120}\)

c: \(C=\dfrac{5}{4}\cdot\dfrac{1}{15}\cdot\dfrac{2}{5}=\dfrac{2}{60}=\dfrac{1}{30}=\dfrac{4}{120}\)

\(D=-3\cdot\dfrac{-7}{12}\cdot\dfrac{1}{-7}=-\dfrac{1}{4}=\dfrac{-30}{120}\)

Vì -50<-30<4<5

nên A<D<B<C

a: \(A=\dfrac{5}{4}\cdot\dfrac{11}{3}\cdot\dfrac{-1}{11}=\dfrac{-5}{12}=\dfrac{-25}{60}=\dfrac{-50}{120}\)

b: \(B=\dfrac{3}{4}\cdot\dfrac{1}{12}\cdot\dfrac{2}{3}=\dfrac{1}{24}=\dfrac{5}{120}\)

c: \(C=\dfrac{5}{4}\cdot\dfrac{1}{15}\cdot\dfrac{2}{5}=\dfrac{2}{60}=\dfrac{1}{30}=\dfrac{4}{120}\)

\(D=-3\cdot\dfrac{-7}{12}\cdot\dfrac{1}{-7}=-\dfrac{1}{4}=\dfrac{-30}{120}\)

Vì -50<-30<4<5

nên A<D<B<C

a) \(\frac{3}{4}-\frac{2}{5}.x=x\)

\(\Rightarrow\frac{-2}{5}.x-x=\frac{-3}{4}\)

\(x.\left(\frac{-2}{5}-1\right)=\frac{-3}{4}\)

\(x.\frac{-7}{5}=\frac{-3}{4}\)

\(x=\frac{-3}{4}:\left(\frac{-7}{5}\right)\)

\(x=\frac{15}{28}\)

b) (2x-1).(3x-1/5).(4-2x) = 0

=> 2x - 1 = 0 => 2x = 1 => x = 1/2

3x-1/5 = 0 => 3x = 1/5 => x = 1/15

4-2x = 0 => 2x = 4 => x = 2

KL: x = 1/2 hoặc x = 1/15 hoặc x = 2