Question

4.(x-3)+5.(x+3)=45

 

Answer 1

\(4(x-3)+5(x+3)=45\\ → 4x-12+5x+15 =45 → 9x=42 \\ → x=\dfrac{14}{3}\)

Vậy \(x=\dfrac{14}{3}\).

 

Answer 2

\(4(x-3)+5(x+3)=45 \\ \Leftrightarrow 4x-12+5x+15=45 \\ \Leftrightarrow 4x+5x=45+12-15 \\ \Leftrightarrow 9x=42 \\ \Leftrightarrow x=42:9 \\ \Leftrightarrow x=\dfrac{42}{9} =\dfrac{14}{3}\)

Answer 3

4.(x-3)+5.(x+3)=45

4x-12+5x+15=45

9x=42

x=\(\dfrac{42}{9}\)

x=\(\dfrac{14}{3}\)