Question

tìm x

Answer 1

a)(x-3)(x+3)-x(x-5)=1

⇔ x²-9-x²+5x=1

⇔5x=10

⇔ x=2

b)5x(x-3)-x²+9=0

⇔5x(x-3)-(x²-9)=0

⇔5x(x-3)-(x-3)(x+3)=0

⇔(x-3)(4x-3)=0

\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\4x-3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=\dfrac{3}{4}\end{matrix}\right.\)