The line through (1, 1) and (3, 5) is given.
Part (a) Find the equation of this line in the form y = mx + c.
Part (b) Hence find the value of x when y = 9.
(a)Find the equation of the line.(2)
(b)Find x when y = 9. You may use your answer from part (a).(2)
(Total for Question 10 is 4 marks)