If $x+\frac{1}{x}=2\cos \theta$ then what is $x^{3}+\frac{1}{x^{3}}$ equal to?

If $0\le x\le \frac{\pi }{2}$ then what is the number of values of x satisfying the equation $\tan x+\sec x=2\cos x$

For the following two (02) items:
A plane P is parallel to the line having direction ratios $\langle1, 3, 2\rangle $ and contains the line of intersection of the planes 6x + 4y - 5z = 2 and x - 2y + 3z = 0

Which of the following are the direction ratios of the line of intersection of the given planes?