Check Your Understanding Practise 1. Determine whether each relation is a function or is not a function. Give a reason for your answer. a) (1, 2), (0, 1), (1, 2), (2, 5) b) (3, 12), (4, 12), (5, 14), (6, 14) c) (1, 2), (2, 3), (3, 4), (4, 5), (5, 6) d) e) X Name y Age 0 0 Naomi 14 1 -1 Wam 15 1 1 Brigid 14 4 -2 Sharon 16 4 2 Arvind 15 f) y g) y . 4- 4- . . 0 -8 -4 0 4 x 2. The formula for the surface area, A, of a sphere with radius r is A = 4r. Write this formula using function notation. 3. The cost to have artwork printed on T-shirts is given by the function C(n) = 3n+ 50, where n is the number of shirts and C is the cost, in dollars. Write this function as a formula in two variables. 4. If f(x)=10x-8, determine a) f(2) b) f(-3) c) x if f(x) = 42 5. If h(x) = x+1, determine a) h(9) b) h(-3) 6. Consider the function p(x) = -4x+2. a) What is the value of p(0)? b) Determine x so that p(x) = -2. c) x if h(x)=-7