20. This equation should read y=3x^2 - 7x + 1

It is a second degree function that forms a parabola passing through (0,1),

(1, -3), (2, -1), (3,7). For every x-value there is exactly one y-value.

21. (9, -7)

22. $19 per day and $0.16 per mile

23. y = -4x + 5

24. [24 + 4(7)^(1/2)] / 29

25. (15)^(1/2) + 2

26. [p(5pmr)^(1/2)] / m

27. 46(x)^(1/2)

28. a. -i

b. 1

c. 12 + 16i

29. [-1 + (17)^(1/2)] / 4