Could someone help me with this?

What is the average rate of change for this function for the interval from x=2 to x=4 ?

Which value of m will create a system of parallel lines with no solution? y = mx - 6 8x - 4y = 12

The length of an intercepted arc of a central angle of a circle is 4 cm. if the radius of the circle is 5 cm what is the measurement of the central angle to the nearest whole degree