In Exercises 1-6, use the First Derivative Test to determine the local'extreme values of the function, and identify any absolute extrema. Support your answers graphically. 1. y=x-x-1 2. y = -2x+6x - 3 3. y = 2x4 4x + 1 - 4. y = xel/x 6. y = (3-x, x