a) \(5x\left(1-2x\right)-3x\left(x+18\right)=0\)
\(\Leftrightarrow5x-10x^2-3x^2-54x=0\)
\(\Leftrightarrow-13x^2-49x=0\)
\(\Leftrightarrow x\left(-13x-49\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\-13x-49=0\Rightarrow x=-\dfrac{49}{13}\end{matrix}\right.\)
Vậy \(x=0\) hoặc \(x=-\dfrac{49}{13}\)
p/s: a thoy ý b thấy hoa mắt quá :v
\(a) 5x(1-2x)-3x(x+18)=0\)
\(5x-10x^2\)\(-3x^2+54x=0\)
\(59x-7x^2=0\)
\(x(59-7x)=0\)
\(\Leftrightarrow x=0\)
\(\Leftrightarrow59-7x=0\Rightarrow x=\dfrac{59}{7}\)
Cậu có ghi đề thiếu câu b không vậy Nguyễn Tường Vy.
\(b\text{)}\)\(5\left(3x^{n+1}-y^{n-1}\right)+3\left(x^{n+1}+5y^{n-1}\right)-5\left(3x^{n+1}\cdot-2y^{n-1}\right)-\left(3^{n-1}-10\right)\text{bằng bao nhiêu vậy}\)
