\[\boxed{\text{350\ (350).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[x + |x| = ?\]
\[x = 7:\ \ \ \ \ \ \ \ \ \]
\[7 + |7| = 7 + 7 = 14.\]
\[x = 10:\ \ \ \ \ \ \]
\[10 + |10| = 10 + 10 = 20.\]
\[x = 0:\ \text{\ \ \ \ \ \ \ \ }\]
\[0 + |0| = 0.\]
\[x = - 3:\ \ \ \ \ \]
\[- 3 + | - 3| = - 3 + 3 = 0.\]
\[x = - 8:\ \ \ \ \ \]
\[- 8 + | - 8| = - 8 + 8 = 0.\]
\[\textbf{а)}\ при\ x \geq 0:\ \ \ \ \ \ \]
\[x + |x| = x + x = 2x.\]
\[\textbf{б)}\ при\ x < 0:\ \ \ \ \ \ \]
\[x + |x| = x - x = 0.\]