Question

[Nguyễn Thanh Vân]

2x⁷ = 3x⁹

Answer 1

[GV Nguyễn Trần Thành Đạt]

\(2x^7=3x^9\\ \Rightarrow\dfrac{x^7}{x^9}=\dfrac{3}{2}\\ \Leftrightarrow\dfrac{1}{x^2}=\dfrac{3}{2}\\ \Leftrightarrow3x^2=2\\ \Rightarrow x^2=\dfrac{2}{3}\\ \Rightarrow x=\pm\sqrt{\dfrac{2}{3}}\)

Answer 2

[Ngô Hải Nam]

`2x^7 =3x^9`

`2x^7 -3x^9 =0`

`x^7 (2-3x^2)=0`

`=>x^7=0` hoặc `2-3x^2 =0`

`=>x=0` hoặc `3x^2 =2`

`=>x=0` hoặc \(x=\sqrt{\dfrac{2}{3}}\) hoặc \(x=-\sqrt{\dfrac{2}{3}}\)