Question

từ dễ đến bình thường 

giải các phương trình sau

1)3=x-8

2)2x=7+x

3)x-(8-x)=4

Answer 1

1. 3=x-8
\(\Leftrightarrow\)x=11
Vậy ...
2. 2x=7+x
\(\Leftrightarrow\)2x-x=7
\(\Leftrightarrow\)x(2-1)=7
\(\Leftrightarrow\)x=7
Vậy ...
3. x-(8-x)=4
\(\Leftrightarrow\)x-8+x=4
\(\Leftrightarrow\)2x-8=4
\(\Leftrightarrow\)2x=12
\(\Leftrightarrow\)x=6
Vậy ...

Answer 2

1) \(3=x-8\)

\(\Leftrightarrow x=11\).

-Vậy \(S=\left\{11\right\}\).

2) \(2x=7+x\)

\(\Leftrightarrow x-7=0\)

\(\Leftrightarrow x=7\).

-Vậy \(S=\left\{7\right\}\).

3) \(x-\left(8-x\right)=4\)

\(\Leftrightarrow2x-8-4=0\)

\(\Leftrightarrow2x-12=0\)

\(\Leftrightarrow x=6\)

-Vậy \(S=\left\{6\right\}\)