= 5/2x - 1

đấy là kết quả rút gọn 

~~~hok tốt~~~

\(3x-\frac{1}{2}x-1\)

\(=\left(3-\frac{1}{2}\right)x-1\)

\(=\frac{5}{2}x-1\)

1)

8=2^3

2)

25=5^2

49-7(13-x)=435

7(13-x)=49-435

7(13-x)=-386

13-x=-386:7

13-x=\(\frac{-386}{7}\)

x=13-\(\frac{-386}{7}\)

x=13+\(\frac{386}{7}\)

x=\(\frac{91}{7}\)+\(\frac{386}{7}\)

x=\(\frac{477}{7}\)

Học tốt

T cho mk nhé

sửa hộ mik x=477/7

https://vn.buddymojo.com/match/igv

\(a,1\frac{5}{8}\)và\(3\frac{1}{4}\)

Tỉ số phần trăm giữa \(1\frac{5}{8}\)và \(3\frac{1}{4}\)là:

\(1\frac{5}{8}:3\frac{1}{4}\cdot100=50\%\)

A = \(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+....+\frac{1}{49.50}\)

A = \(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{49}-\frac{1}{50}\)

A = \(1-\frac{1}{50}=\frac{49}{50}\)

\(A=\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+...+\frac{1}{49\cdot50}\)

\(A=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{49}-\frac{1}{50}\)

\(A=1-\frac{1}{50}\)

\(A=\frac{49}{50}\)

1 mũ 2 = 1

\(a,\frac{1}{2}-\left(\frac{2}{3}x-\frac{1}{3}=\frac{2}{3}\right)\)

\(\frac{2}{3}x-\frac{1}{3}=-\frac{1}{6}\)

\(\frac{2}{3}x=\frac{1}{6}\)

\(x=\frac{1}{4}\)

\(\frac{1}{2}-\left(\frac{2}{3}.x-\frac{1}{3}\right)=\frac{2}{3}\)

\(\Rightarrow\frac{2}{3}.x-\frac{1}{3}=\frac{1}{2}-\frac{2}{3}=\frac{-1}{6}\)

\(\Rightarrow\frac{2}{3}.x=\frac{-1}{6}+\frac{1}{3}=\frac{1}{6}\)

\(\Rightarrow x=\frac{1}{6}:\frac{2}{3}=\frac{1}{4}\)

|x + 1| = |x - 2|

=> \(\orbr{\begin{cases}x+1=x-2\\x+1=2-x\end{cases}}\Leftrightarrow\orbr{\begin{cases}0x=-3\left(\text{loại}\right)\\2x=1\end{cases}}\Leftrightarrow x=\frac{1}{2}\)

Vậy x = 1/2

b) Ta có 2|x - 2| + |2 - x| = 15

<=> 2|x - 2| + |x - 2| = 15

<=> 3|x - 2| = 15

<=> |x - 2| = 5

<=> \(\orbr{\begin{cases}x-2=5\\x-2=-5\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=7\\x=-3\end{cases}}\)

a) |x + 1| = |x - 2|

<=> \(\orbr{\begin{cases}x+1=x-2\\x+1=2-x\end{cases}}\)

<=> \(\orbr{\begin{cases}0x=-3\\2x=1\end{cases}}\)

<=> \(x=\frac{1}{2}\)

Vậy x = 1/2

b) Ta có: 2|x - 2| + |2 - x| = 15

<=> 3|x - 2| = 15

<=> |x - 2| = 5

<=> \(\orbr{\begin{cases}x-2=5\\x-2=-5\end{cases}}\)

<=> \(\orbr{\begin{cases}x=7\\x=-3\end{cases}}\)

Vậy x thuộc {7; -3}