Question

[Bùi Bảo Ngọc]

GIÚP MÌNH BÀI NÀY VỚI Ạ!

tìm x: 5x( 3x - 2 ) = 4 - 9x²

Answer 1

[Yen Nhi]

\(5x.\left(3x-2\right)=4-9x^2\)

\(\Rightarrow5x.\left(3x-2\right)-\left(4-9x^2\right)=0\)

\(\Rightarrow5x.\left(3x-2\right)+\left(9x^2-4\right)=0\)

\(\Rightarrow5x.\left(3x-2\right)+\left(3x-2\right).\left(3x+2\right)=0\)

\(\Rightarrow\left(3x-2\right).\left(5x+3x+2\right)=0\)

\(\Rightarrow\left(3x-2\right).\left(8x+2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}3x-2=0\\8x+2=0\end{cases}}\Rightarrow\orbr{\begin{cases}3x=2\\8x=-2\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{2}{3}\\x=\frac{-1}{4}\end{cases}}\)

Answer 2

[Bùi Bảo Ngọc]

cảm ơn bạn