Let for \( f(x) = 7 \tan^{8} x + 7 \tan^{6} x - 3 \tan^{4} x - 3 \tan^{2} x \), \( I_{1} = \int_{0}^{\pi/4} f(x) \, dx \) and \( I_{2} = \int_{0}^{\pi/4} x \, f(x) \, dx \). Then \( 7 I_{1} + 12 I_{2} \) is equal to:
\( 2\pi \)
\( \pi \)
\( 1 \)
\( 2 \)