§ Задание 321
\[\boxed{\text{4.\ 321}}\]
\[\textbf{а)}\ a = a^{2}\]
\[a = 0;\ \ a = 1.\]
\[\textbf{б)}\ a = a^{3}\]
\[a = 0;\ \ a = 1;\ \ a = - 1.\]
\[\textbf{в)}\ a^{2} = a^{3}\]
\[a = 0;\ \ a = 1.\ \]
\[\boxed{\text{4.\ 321}}\]
\[\textbf{а)}\ a = a^{2}\]
\[a = 0;\ \ a = 1.\]
\[\textbf{б)}\ a = a^{3}\]
\[a = 0;\ \ a = 1;\ \ a = - 1.\]
\[\textbf{в)}\ a^{2} = a^{3}\]
\[a = 0;\ \ a = 1.\ \]