\(\left(19x+2.5^2\right):14=\left(13-8\right)^2-4^2\)

\(\Rightarrow\left(19x+50\right):14=25-16\)

\(\Rightarrow19x+50=9.14=126\)

\(\Rightarrow19x=76\)

\(\Rightarrow x=76:19=4\)

(19x+2.5²):14 =(13-8)²-4²

(19x + 50):14  = 5²-4²

(19x + 50):14  = 9

19x + 50          = 9.14

 19x+50           = 126

  19x                 =76

     x                   =76:19

     x                   =4

Chúc các bn học tốt ah🥰🥰

(19x + 2 . 5²) : 14 = (13 - 8)² - 4²

(19x + 50) : 14 = (13 - 8)² - 4² = 25 - 16 = 9

19x + 50 = 9 . 14 = 126

19x = 126 - 50 = 76

x = 76 : 19 = 4

Chúc bạn học tốt!!!!!

( 19x + 2.5² ) : 14 = ( 13 - 8 )²- 4 ²

( 19x + 2.5² ) : 14 = 5²- 4 ²

( 19x + 2.5² ) : 14 = 25- 16

( 19x + 2.5² ) : 14 =9

( 19x + 50 ) : 14 =9

 19x + 50=9 . 14

 19x + 50=126

19x=126-50

19x=76

x=76:19

x=4

vbawngf 4 bạn nhé chắc chắn 100%

gan gon hon nha

(19x+2*5^2)/14=(13-8)^2-4^

(19x+2*25)/14=(13-8)^2-16

(19x+2.25)/14=5^-16

(19x+2.25)/14=25-16

(19+2.25)=9*14

19X=126+50

x=76/19

x=4

a) \(\left(19x+2\cdot5^2\right):14=\left(13-8\right)^2-4^2\)

\(\Leftrightarrow\left(19x+2\cdot25\right):14=5^2-4^2\)

\(\Leftrightarrow19x+50=\left(25-16\right)\cdot14\)

\(\Leftrightarrow19x+50=9\cdot14\)

\(\Leftrightarrow19x+50=126-50\)

\(\Leftrightarrow19x=76\)

\(\Leftrightarrow x=76:19\)

\(\Leftrightarrow x=4\)

b) \(x+\left(x+1\right)+\left(x+2\right)+...+\left(x+30\right)=1240\)

\(\Leftrightarrow\left(x+x+x+x...+x\right)+\left(1+2+3+...+30\right)=1240\)

\(\Leftrightarrow31x+\frac{\left[\left(30-1\right):1+1\right]\cdot\left(30+1\right)}{2}=1240\)

\(\Leftrightarrow31x+465=1240\)

\(\Leftrightarrow31x=775\)

\(\Leftrightarrow x=25\)

c)\(11-\left(-53+x\right)=97\)

\(\Leftrightarrow-53+x=-86\)

\(\Leftrightarrow x=-33\)

d) \(-\left(x+84\right)+213=-16\)

\(\Leftrightarrow-\left(x+84\right)=-229\)

\(\Leftrightarrow x+84=229\)

\(\Leftrightarrow x=145\)

a, (19x+2.5²) : 14 = (13-8)² - 4²

(19x + 2.25) : 14 = 5² - 4²

(19x + 50) : 14 = 25 - 16

(19x + 50) : 14 = 9

19 x + 50 = 9.14

19x + 50 = 126 

19x = 126 - 50

19x = 76

x = 76 : 19

x = 4

vậy____

b) x + (x + 1) + (x + 2) + (x + 3)+.....+(x+30) = 1240

(x+x+x+...+x) + (1+2+3+...+30) = 1240

31x + 465 = 1240

31x = 1240 - 465

31x = 775

x = 775 : 31

x = 25

vậy____

c) |x + 7| = 20 + 5.(-3)

|x + 7| = 20 + (-15)

|x + 7| = 5

\(\Rightarrow\orbr{\begin{cases}x+7=5\\x+7=-5\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=5-7\\x=-5-7\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-2\\x=-12\end{cases}}\)

vậy_____

câu b sai rồi,thế này mới đúng nè:

b,(19x+2.5⁵):4=(13-8)²-4²

(19x+2.5²):14=5²-4²

(19x+2.5²):14=8

19x+2.5²+126

19x+50=126

19x=76

x=4

sai rồi 8 phải sửa là 9 mới đúng

Ta có : \(\left(19x+2\cdot5^2\right):14=\left(13-8\right)^2-4\)

     \(\Leftrightarrow\left(19x+2\cdot25\right):14=5^2-4\) 

      \(\Leftrightarrow\left(19x+50\right)=21\cdot14\)
      \(\Leftrightarrow19x+50=294 \)
        \(\Leftrightarrow19x=294-50\)
         \(\Leftrightarrow x=\frac{244}{19}=12\frac{16}{19}\)
    

( 19x + 2 . 5\(^2\)) : 14 = ( 13 - 8 )\(^2\) - 4

 ( 19x + 2 . 25 ) : 14  =      5\(^2\)- 4

 ( 19x +  50 )      : 14 =   25 - 4

 ( 19x + 50 )       : 14 =   21

    19x + 50                = 21 . 14

    19x + 50                =    294

    19x                         =    294 - 50

    19x                         =         \(\frac{244}{19}\)

( 19x + 2 . 5² ) : 14 = ( 13 - 8 )² - 4²

( 19x + 2 .25 ) : 14 = 5² - 4²

( 19x + 100 ) : 14 = 25 -  16

( 19x + 100 ) : 14 = 9

( 19x + 100 )    = 76

19x                = -24

   x      ko tìm đk