\[\boxed{\mathbf{1104}\mathbf{.}}\]
\[1)\ 1 - \sqrt{2}\sin a =\]
\[= \sqrt{2}\left( \frac{\sqrt{2}}{2} - \sin a \right) =\]
\[= \sqrt{2}\left( \sin\frac{\pi}{4} - \sin a \right) =\]
\[= 2\sqrt{2}\sin\left( \frac{\pi}{8} - \frac{a}{2} \right)\cos\left( \frac{\pi}{8} + \frac{a}{2} \right)\]
\[2)\sin^{2}a - 0,75 = \frac{1}{2} -\]
\[- \frac{1}{2}\cos{2a} - 0,75 =\]
\[= - \frac{1}{2}\cos{2a} - \frac{1}{4} =\]
\[= - \frac{1}{2}\left( \cos{2a} + \frac{1}{2} \right) =\]
\[= - \frac{1}{2} \cdot \left( \cos{2a} + \cos\frac{\pi}{3} \right) =\]
\[= - \cos\left( a + \frac{\pi}{6} \right)\cos\left( a - \frac{\pi}{6} \right)\]
\[3)\sin x + \sqrt{3}\cos x =\]
\[= 2 \cdot \left( \frac{1}{2}\sin x + \frac{\sqrt{3}}{2}\cos x \right) =\]
\[= 2 \cdot \left( \cos\frac{\pi}{3}\sin x + \sin\frac{\pi}{3}\cos x \right) =\]
\[= 2\sin\left( x + \frac{\pi}{3} \right)\]
\[4)\ \sqrt{3}\sin x - \cos x =\]
\[= 2 \cdot \left( \frac{\sqrt{3}}{2}\sin x - \frac{1}{2}\cos x \right) =\]
\[= 2\sin\left( x - \frac{\pi}{6} \right)\]