Guys please answer question #17 and 18 below please and thank you.

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?

These tables represent a quadratic function with a vertex at (0, -1). what is the average rate of change for the interval from x = 9 to x = 10?

Identify the function that contains the data in the following table: x     -2         0         2         3         5     f(x)     5         3         1         2         4     possible answers: f(x) = |x| + 1 f(x) = |x - 2| f(x) = |x - 2| - 1 f(x) = |x - 2| + 1