Помогите пожалуйста

Решите задачу:

$log_{2}(7) + log_{2}(2) + log_{2}(3) = log_{2}(x) \\ log_{2}( 7\times 2 \times 3) = log_{2}(x) \\ log_{2}(x ) = log_{2}(42) \\ x = 42$
$log_{3}(18) - log_{3}(2) - log_{3}(2) = log_{3}(x) \\ log_{3}( \frac{18}{2 \times 2} ) = log_{3}(x) \\ x = \frac{9}{2} = 4.5$
$log_{13}(x) = 2 log_{13}(2) \\ log_{13}(x) = log_{13}( {2}^{2} ) \\ x = 4$