=> 4(x2 - 2x + 1) - 9(x2 + 4x + 4) = 0
=> 4x2 - 8x + 4 - 9x2 - 36x - 36 = 0
=> -5x2 - 44x - 32 = 0
Có: \(\Delta'=\left(-22\right)^2-\left(-32\right)\left(-5\right)=324\)
\(\Rightarrow\sqrt{\Delta'}=\sqrt{324}=18\)
\(\Rightarrow x=-\frac{4}{5}\) hoặc \(x=-8\) (loại)
Vậy x = -4/5