Consider the following function. f( x ) = X - 15 Write the function in the form y = ax* + bx + c. Give the values of a, b, and c. b = C Determine the x-coordinate of the vertex of the graph. X = Determine the y-coordinate of the vertex of the graph. Y = Find the vertex of the graph. ( x, y ) = Is the value of a greater than 0 or less than 0? O greater than 0 O less than 0 Determine whether the graph opens up or down. O The graph opens up. The graph opens down