Question

помогите, пожалуйста!​ б и г

Answer 1

$1)\ \ \dfrac{(x-7)(x+3)}{5x}\ \ \ \Longleftrightarrow \ \ \ \left\{\begin{array}{l}(x-7)(x+3)=0\\x\ne 0\end{array}\right\ \ \ \Longrightarrow \ \ \ x_1=7\ ,\ x_2=-3$

$2)\ \ \dfrac{(x+2)(x-1)}{3x}=0\ \ \ \Longleftrightarrow \ \ \ \left\{\begin{array}{l}(x+2)(x-1)=0\\x\ne 0\end{aray}\right\ \ \ \Longrightarrow \ \ \ x_1=-2\ ,\ x_2=1$

$3)\ \ \ \dfrac{x^2-5x}{x^2-25}=0\ \ \ \Longleftrightarrow \ \ \left\{\begin{array}{l}x^2-25x=0\\x^2-25\ne 0\end{array}\right\ \ \left\{\begin{array}{l}x\, (x-5)=0\\(x-5)(x+5)\ne 0\end{array}\right\\\\\\\left\{\begin{array}{l}x_1=0\ \ ,\ \ x_2=5\\x\ne -5\ ,\ x\ne 5\end{array}\right\ \ \ \Longrightarrow \ \ x=0$

$4)\ \ \dfrac{x^2+4x}{x^2-16}=0\ \ \Longrightarrow \ \ \dfrac{x\, (x+4)}{(x-4)(x+4)}=0\ \ ,\ \ \dfrac{x}{x-4}=0\ \ \Longleftrightarrow \\\\\\\left\{\begin{array}{l}x=0\\x\ne 4\end{array}\ \ \ \Longrightarrow \ \ \ x=0$