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

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

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

\(\Rightarrow19x=76\)

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

(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🥰🥰

Ta có :

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

\(\Leftrightarrow\)\(\frac{19x+2.25}{14}=5^2-4^2\)

\(\Leftrightarrow\)\(\frac{19x+50}{14}=25-16\)

\(\Leftrightarrow\)\(\frac{19x+50}{14}=9\)

\(\Leftrightarrow\)\(19x+50=126\)

\(\Leftrightarrow\)\(19x=76\)

\(\Leftrightarrow\)\(x=\frac{76}{19}\)

\(\Leftrightarrow\)\(x=4\)

Vậy \(x=4\)

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_____

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) \(-\left(x+84\right)+213=-16\)

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

\(\Leftrightarrow x+84=229\)

\(\Leftrightarrow x=145\)

\(2.3^x=10.3^{12}+8.27^4\)

\(2.3^x=10.531441+8.531441\)

\(2.3^x=\left(10+8\right).531441\)

\(2.3^x=18.531441\)

\(2.3^x=9565938\)

\(3^x=9565938:2\)

\(3^x=4782969\)

\(3^x=3^{14}\)

\(\Rightarrow x=14\)

Thanks!

1) ( 2x -15 )⁵ = ( 2x - 15 )³

( 2x -15 )⁵ - ( 2x - 15 )³ = 0

( 2x - 15 )³ .  [ ( 2x - 15 )² - 1 ] = 0

\(\orbr{\begin{cases}\left(2x-15\right)^3=0\\\left(2x-15\right)^2-1=0\end{cases}}\)

\(\orbr{\begin{cases}2x-15=0\\2x-15=1\end{cases}}\)

\(\orbr{\begin{cases}2x=15\\2x=16\end{cases}}\)

\(\orbr{\begin{cases}x=\frac{15}{2}\\x=8\end{cases}}\)

c,11-(-53+x)=97

-53+x=11-97

-53+x= -86

x = -86-(-53)

x= -33

\(\left(19x+2.5^1\right):14=\left(13-8\right)^2-4^2.\)

\(\left(19x+10\right):14=5^2-4^2\)

\(\left(19x:4\right)+\left(10:4\right)=25-16\)

\(\left(19x:4\right)+\frac{5}{2}=9\)

\(19x:4=9-\frac{5}{2}\)

\(19x:4=\frac{13}{2}\)

\(19x=\frac{13}{2}.4=26\)

\(x=\frac{26}{19}\)

B/ \(-\left(x+84\right)+213=\left(-16\right).\)

\(-x-84+213=-16\)

\(-x+129=-16\)

\(-x=\left(-145\right)\)

\(\Rightarrow x=145\)