9 DETAILS Verify that the Intermediate Value Theorem applies to the indicated interval and find the value of c guaranteed by the theorem. f(x) = x2 + 4x + 1, [0, 5], /c) = 13 c = 10 DETAILS Determine the points at which the graph of the function has a horizontal tangent line. f( x ) = - x2 X - 6 ( x, y ) = ( (smaller x-value) ( x , y ) = (larger x-value) 11 DETAILS Find k such that the line is tangent to the graph of the function. Function Line f ( x ) = KVx y = 4x + 4 k =