a)\(5\left(2x-1\right)-4\left(8-3x\right)=7\)

\(\Leftrightarrow10x-5+12x-32=7\)

\(\Leftrightarrow22x-37=7\)

\(\Leftrightarrow22x=44\Rightarrow x=2\)

b)\(5x\left(x-5\right)-x\left(2x+3\right)=26\)

\(\Leftrightarrow5x^2-25x-2x^2-3x=26\)

\(\Leftrightarrow3x^2-28x-26=0\)

\(\Leftrightarrow3\left(x-\dfrac{14}{3}\right)^2-\dfrac{274}{3}=0\)

\(\Rightarrow x=\dfrac{14}{3}\pm\dfrac{\sqrt{274}}{3}\)

\(x=3y\); \(y-x=26\)

từ \(y-x=26\Rightarrow x=y-26\)

thay \(x=y-26\), ta được:

\(y-26=3y\)

\(\Rightarrow2y=-26\)

\(\Rightarrow y=-13\)mà  \(x=3y\Rightarrow x=3\cdot\left(-13\right)=-39\)

vậy \(x=-39;y=-13\)

Ta có : \(\frac{x}{5}=\frac{y}{7}\Rightarrow5y=7x\Rightarrow x=\frac{5y}{7}\)

Thay \(x=\frac{5y}{7}\)vào biểu thức \(2x+y=26\);ta được: 

\(\frac{2.5y}{7}+y=26\Rightarrow10y+7y=26.7\Rightarrow17y=182\Rightarrow y=\frac{182}{17}\)

Do đó : \(x=\frac{\frac{5.182}{17}}{7}=\frac{130}{17}\)

a) \(2x\left(x-5\right)-x\left(3+2x\right)=26\)

\(\Rightarrow2x^2-10x-3x-2x^2=26\)

\(\Rightarrow-13x=26\Rightarrow x=-2\)

b) \(3x\left(1-2x\right)+2\left(3x+7\right)=29\)

\(\Rightarrow3x-6x^2+6x+14=29\)

\(\Rightarrow-6x^2+9x-15=0\)

\(\Rightarrow-6\left(x^2-\dfrac{3}{2}x+\dfrac{9}{16}\right)-\dfrac{93}{8}=0\)

\(\Rightarrow-6\left(x-\dfrac{3}{4}\right)^2-\dfrac{93}{8}=0\)(vô lý)

Vậy \(S=\varnothing\)

a. \(2x^2-10x-3x-2x^2=26\Leftrightarrow-13x=26\Leftrightarrow x=-2\)

a: \(\Leftrightarrow2x^2-10x-3x-2x^2=26\)

hay x=-2

a) 2x (x - 5) - x (3 + 2x) = 26

=>  2x² - 10x - (3x - 2x²) = 26

=> 2x² - 10x - 3x - 2x² = 26

=> -13x = 26    => x = 26 : (-13) = -2

xin loi nhung hoi nhiu mik viet cau tra loi dc ko - Nguyễn Diệu Thảo

Đúng thì TICK nka !

2x(x-5)-x(3+2x)= 26

2x^2-10x-3x-2x^2=26

-13x=26 x=-2

Vậy x=-2.

b) giống

  a, 2x ( x - 5 ) -x ( 3 + 2x ) = 26

=> 2x^2 - 10x - 3x - 2x^2 = 26

=> -13x = 26

=> x = -2

b, ( x - 7)  ( x - 5 ) - x ( x + 2 )= 4

=> x^2 - 12x + 35 - x^2 - 2x = 4

=> -14x = -31

=> x = 31/14

\(a,2x\left(x-5\right)-x\left(3+2x\right)=26\)

\(\Leftrightarrow2x^2-10x-3x-2x^2=26\)

\(\Leftrightarrow-13x=26\)

\(\Leftrightarrow x=-2\)

\(\Rightarrow S=\left\{-2\right\}\)

\(b,\left(x-7\right)\left(x-5\right)-x\left(x+2\right)=4\)

\(\Leftrightarrow x^2-5x-7x+35-x^2-2x-4=0\)

\(\Leftrightarrow-14x+31=0\)

\(\Leftrightarrow-14x=-31\)

\(\Leftrightarrow x=\frac{31}{14}\)

\(\Rightarrow S=\left\{\frac{31}{14}\right\}\)

Trả lời:

a, 2x ( x - 5 ) - x ( 3 + 2x ) = 26 

<=> 2x² - 10x - 3x - 2x² = 26 

<=> - 13x = 26 

<=> x = - 2

Vậy x = - 2 là nghiệm của pt.

b, ( x - 7 )( x - 5 ) - x ( x + 2 ) = 4

<=> x² - 5x - 7x + 35 - x² - 2x = 4

<=> - 14x + 35 = 4

<=> - 14x = - 31

<=> x = 31/14

Vậy x = 31/14 là nghiệm của pt.

2: =>(3x-7)^2=25/144=(5/12)^2

=>3x-7=5/12 hoặc 3x-7=-5/12

=>3x=5/12+7=89/12 hoặc 3x=7-5/12=79/12

=>x=89/36 hoặc x=79/36

3:Sửa đề: |2x-3|=|x+1|

=>2x-3=x+1 hoặc 2x-3=-x-1

=>x=4 hoặc 3x=2

=>x=2/3 hoặc x=4

4: =>3x+1=5 hoặc 3x+1=-5

=>3x=4 hoặc 3x=-6

=>x=-2 hoặc x=4/3

1: =>\(2x-7=\sqrt[3]{\dfrac{26}{63}}\)

=>\(2x=\sqrt[3]{\dfrac{26}{63}}+7\)

=>\(x=\dfrac{1}{2}\cdot\left(\sqrt[3]{\dfrac{26}{63}}+7\right)\)

a) x - 12 - 2x - 32 = -11

-x - 44 = -11

-x  = 33

x = -33 

a/ (x-12)-(2x+31)=-6-5

    x-12-2x-31=-11

    -x=(-11)+43

-x=32

=> x=-32

a/ (x-12)-(2x+31)=-6-5

    x-12-2x-31=-11

    -x=(-11)+43

-x=32

=> x=-32