i need help understanding and showing work for both these questions

18) Does the graph of the function y = tan x - x have any horizontal tangents in the interval OS x S 2nt? If so, where? A) No B) Yes, at x = _ 7 X 2 C) Yes, at x = 0, X = 71, X = 2n D) Yes, at X = 7Suppose u and v are differentiable functions of x. Use the given values of the functions and their derivatives to find the value of the indicated derivative. 11) u(1) = 2, u'(1) = -7, v(1) = 6, v '(1) = -4. d (2u - 4v) at x = 1 dx A) -30 B) -20 C) 28 D) 2