Q1- A scientist begins with 35 grams of a radioactive substance . After 5 days, the sample has decayed to 20 grams. Find the half-life of this substance. (solve this problem algebraically) (give to 2 decimal places)

Q2- Graph the Piecewise defined function f(x), and find the domain of the function. (Use an open circle represent a point which is not included and a solid dot to indicate a point which is on the graph.)

4, if X < -2.

F(x)=-X^2, if -2 <= X <= 0

Sqrt (x), if 0 < X < 4