Вправа 622 алгебра Бевз гдз 7 клас
$$\begin{aligned}
&\text { № } 622\\
&\begin{aligned}
& \text { a) } x^4-x^2=0 \\
& x^2\left(x^2-1\right)=0 \\
& x^2(x-1)(x+1)=0 \\
& {\left[\begin{array}{l}
x^2=0 \\
x-1=0 \\
x+1=0
\end{array}\right.} \\
& {\left[\begin{array}{l}
x=0 \\
x=1 \\
x=-1
\end{array}\right.}
\end{aligned}\\
&\begin{aligned}
& \text { b) } x^3-25 x=0 \\
& x\left(x^2-25\right)=0 \\
& x(x-5)(x+5)=0 \\
& {\left[\begin{array}{l}
x=0 \\
x-5=0 \\
x+5=0
\end{array}\right.} \\
& {\left[\begin{array}{l}
x=0 \\
x=5 \\
x=-5
\end{array}\right.}
\end{aligned}\\
&\begin{aligned}
& \text { c) } x^4-0,04 x^2=0 \\
& x^2\left(x^2-0,04\right)=0 \\
& x^2(x-0,2)(x+0,2)=0 \\
& x_1=0 ; x_2=0,2 ; x_3=-0,2 .
\end{aligned}
\end{aligned}
$$
вправи поруч
