a) 2x -18 = 10

    =>2x = 28

    => x = 14

b) 3x + 26 = 5

=> 3x = -21

=> x = -7

Ai làm cả 2 bài mình tích

x+8/10=340/360-324/360

x+8/10=16/360

x=16/360-80/360

x=-64/360

x-1/10=1/15

x=1/15+1/10

x=10/150-15/150

x=-5//150=-1/30

(3/5-2)+13/20=5/6

(3/5-10/5)+13/20

-7/5+13/20=5/6

a. 18 - 17 + x = -3 - 5

18 -17 + x =-8

1 + x = -8 

  x = -8 - 1

x =-9

​b\ |x-3|=4

suy ra : x - 3 = 4 suy ra x = 4 + 3 suy ra x = 7

suy ra : x - 3 = - 4 suy ra x = -4 + 3 suy ra x = -1

6x(3x + 5) - 2x(3x - 2) + (17 - x)(x - 1) + x(x - 18) = 0

=> (18x² - 6x² - x² + x²) + (30x + 4x - 16x - 18x) - 17 = 0

=> 12x² - 17 = 0

=> 12x² = 17

=> x² = 17/12

=> \(\orbr{\begin{cases}x=\sqrt{\frac{17}{12}}\\x=-\sqrt{\frac{17}{12}}\end{cases}}\)

\(6x\left(3x+5\right)-2x\left(3x-2\right)+\left(17-x\right)\left(x-1\right)+x\left(x-18\right)=0\)

\(\Leftrightarrow9x^2+30x-6x^2+4x+17x-17-x^2+x+x^2-18x=0\)

\(\Leftrightarrow3x^2+34x-17=0\) ( vô nghiệm ) 

6x( 3x + 5 ) - 2x( 3x - 2 ) + ( 17 - x )( x - 1 ) + x( x - 18 ) = 0

<=> 18x² + 30x - 6x² + 4x - x² + 18x - 17 + x² - 18x = 0

<=> 12x² + 34x - 17 = 0

\(\Delta'=b'^2-ac=\left(\frac{b}{2}\right)^2-ac=\left(\frac{34}{2}\right)^2-12\cdot\left(-17\right)=289+204=493\)( không muốn xài Delta nữa đâu nhưng ... :)) )

\(\Delta'>0\)nên phương trình đã cho có hai nghiệm phân biệt

\(\hept{\begin{cases}x_1=\frac{-b'+\sqrt{\Delta'}}{a}=\frac{-17+\sqrt{493}}{12}\\x_2=\frac{-b'-\sqrt{\Delta'}}{a}=\frac{-17-\sqrt{493}}{12}\end{cases}}\)

Vậy ...

ta có 2x-5+16=15-5x+3 => 7x=7=>x=1

(x-2)(x+5)-18=x^2-4x => x^2+3x-10-18=x^2-4x =>7x=28 =>x=4