(x-5).3/10=2000+5

(x-5).3/10=2005

x-5=2005:3/10

x-5=2005.10/3

x-5=20050/3

x=20050/3 +5

x=20065/3

\(\left(x-5\right)\)\(.\)\(\frac{30}{100}\)\(=\)\(20\times100+5\)

\(\left(x-5\right)\)\(.\)\(\frac{3}{10}\)\(=\)\(2005\)

\(\left(x-5\right)\)\(=\)\(2005\)\(\div\)\(\frac{3}{10}\)

\(\left(x-5\right)\)\(=\)\(2005\)\(.\)\(\frac{10}{3}\)

\(\left(x-5\right)\)\(=\)\(\frac{20050}{3}\)

\(x=\frac{20055}{3}\)

Hok tốt

x=65 nhé

x = 65 đấy bạn 

nếu chưa chắc chắn thì bạn tính thử đi

chúc bạn học giỏi

ĐKXĐ: \(x\notin\left\{0;-20\right\}\)

\(\left\{{}\begin{matrix}y=20+x\\\dfrac{100}{x}-\dfrac{100}{20+x}=\dfrac{5}{6}\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=x+20\\\dfrac{20}{x}-\dfrac{20}{x+20}=\dfrac{1}{6}\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=x+20\\\dfrac{20x+400-20x}{x\left(x+20\right)}=\dfrac{1}{6}\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=x+20\\\dfrac{400}{x\left(x+20\right)}=\dfrac{1}{6}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=x+20\\x\left(x+20\right)=2400\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=x+20\\x^2+20x-2400=0\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=x+20\\\left(x+60\right)\left(x-40\right)=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=x+20\\\left[{}\begin{matrix}x+60=0\\x-40=0\end{matrix}\right.\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}y=x+20\\x\in\left\{-60;40\right\}\end{matrix}\right.\)(nhận)

=>\(\left[{}\begin{matrix}\left\{{}\begin{matrix}x=-60\\y=x+20=-60+20=-40\end{matrix}\right.\\\left\{{}\begin{matrix}x=40\\y=x+20=60\end{matrix}\right.\end{matrix}\right.\)

b, 30(x+20) - 6(x-5) - 24 - x =100

30x+600-6x+30-24-x=100

30x-6x+x=100-600-30-24

25x=-554

x=\(-\frac{554}{25}\)

cho li-ke nha

a, -12 . (x-5)+ 7 . ( 3-x ) =15

-12x+60+21-7x=15

-12x7x=15-60-21

-21x=-66

x=  -544/25

tick nha 

=) đây là bài giải bằng cách lập pt mà nãy bạn đã đăng nè:v mà giải thì ra vô nghiệm á bạn nên mik ko có làm:v

\(\dfrac{30-x}{30}=\dfrac{8}{15}\)

\(\Rightarrow\left(30-x\right)15=30\times8\)

\(\Rightarrow\left(30-x\right)15=240\)

\(\Rightarrow30-x=240:15\)

\(\Rightarrow30-x=16\)

\(\Rightarrow x=30-16\)

\(\Rightarrow x=14\)

__

\(\dfrac{x+30}{72}=\dfrac{5}{8}\)

\(\Rightarrow\left(x+30\right)8=5\times72\)

\(\Rightarrow\left(x+30\right)8=360\)

\(\Rightarrow x+30=360:8\)

\(\Rightarrow x+30=45\)

\(\Rightarrow x=45-30\)

\(\Rightarrow x=15\)