Question

Mn ơi giải giúp em câu này với ah

Answer 1

`<=> 2x - 5 - 7 + x = x - 3 - 12 + 3x`

`<=> 3x - 12 = 4x - 15`

`<=> x = 3`

Answer 2

\(\left(2x-5\right)-\left(7-x\right)=\left(x-3\right)-3\left(4-x\right)\\ 2x-5-7+x=x-3-12+3x\\ 2x+x-x-3x=-3-12+5+7\\ -x=-3\\ x=3\)

Answer 3

\(\left(2x-5\right)-\left(7-x\right)=\left(x-3\right)-3\left(4-x\right)\)

\(\Rightarrow3x-12=\left(x-3\right)-\left(12-3x\right)\)

\(\Rightarrow3x-12=4x-15\)

\(\Rightarrow3x+3=4x\)

\(\Rightarrow4x-3x=3\Rightarrow x=3\)