Consider the function. f(x) = x²-2x+4 Step 1 of 2: Find all values of x that correspond to horizontal tangent lines. Select "None" if the function does not have any values of x that correspond to horizontal tangent lines. Consider the function. f(x) = x²-2x+4 Step 2 of 2: Determine the open intervals on which the function is increasing and on which the function is decreasing. Enter to indicate the interval is empty.