What does "C" represent and how do you evaluate this?

Which quadratic function best fits this data? x y 1 32 2 78 3 178 4 326 5 390 6 337 a. y=11.41x2+154.42x−143.9 b. y=−11.41x2+154.42x−143.9 c. y=11.41x2+154.42x+143.9 d. y=−11.41x2+154.42x+143.9

With these: 18/36 = 1/? missing number change 1 5/8 to improper fraction. change 19/5 to a mixed number.

Which of the following is best modeled using a linear equation y=ax+b, where a is less than 0?