Question

Tìm x

\(2.\left(x-3\right)-5\left(x-4\right)=15\)

Answer 1

2.(x-3)-5.(x-4)=15

\(\Leftrightarrow2x-6-5x+20\)

\(\Leftrightarrow x.\left(2-5\right)-6+20=15\)

\(\Leftrightarrow-3x+14=15\)

\(\Leftrightarrow-3x=1\)

\(\Leftrightarrow x=\dfrac{-1}{3}\)

Answer 2

\(2\left(x-3\right)-5\left(x-4\right)=15\)

\(\Rightarrow2x-6-5x+20=15\)

\(\Rightarrow-6+20-15=5x-2x\)

\(\Rightarrow-1=3x\)

\(\Rightarrow x=-\dfrac{1}{3}\)