\[\boxed{\mathbf{989}\mathbf{.}}\]
\[1)\ f(x) = 3\cos x - 4\sin x;\]
\[F(x) = 3 \bullet \sin x - 4 \bullet \left( - \cos x \right) =\]
\[= 3\sin x + 4\cos x + C.\]
\[2)\ f(x) = 5\sin x + 2\cos x;\]
\[F(x) = 5 \bullet \left( - \cos x \right) + 2 \bullet \sin x =\]
\[= 2\sin x - 5\cos x + C.\]
\[3)\ f(x) = e^{x} - 2\cos x;\]
\[F(x) = e^{x} - 2\sin x + C.\]
\[4)\ f(x) = 3e^{x} - \sin x;\]
\[F(x) = 3 \bullet e^{x} - \left( - \cos x \right) =\]
\[= 3e^{x} + \cos x + C.\]
\[5)\ f(x) = 5 - e^{- x} + 3\cos x;\]
\[F(x) =\]
\[= 5 \bullet \frac{x^{1}}{1} - \left( - e^{- x} \right) + 3 \bullet \sin x =\]
\[= 5x + e^{- x} + 3\sin x + C.\]
\[6)\ f(x) = 1 + 3e^{x} - 4\cos x;\]
\[F(x) =\]
\[= 1 \bullet \frac{x^{1}}{1} + 3 \bullet e^{x} - 4 \bullet \sin x =\]
\[= x + 3e^{x} - 4\sin x + C.\]
\[7)\ f(x) = 6\sqrt[3]{x} - \frac{2}{x} + 3e^{x} =\]
\[= 6 \bullet x^{\frac{1}{3}} - \frac{2}{x} + 3e^{x};\]
\[F(x) =\]
\[= 6 \bullet x^{\frac{4}{3}}\ :\frac{4}{3} - 2 \bullet \ln x + 3 \bullet e^{x} =\]
\[= \frac{9}{2}x\sqrt[3]{x} - 2\ln x + 3e^{x} + C.\]
\[8)\ f(x) = \frac{4}{\sqrt{x}} + \frac{3}{x} - 2e^{- x} =\]
\[= 4 \bullet x^{- \frac{1}{2}} + \frac{3}{x} - 2e^{- x};\]