4^2= 16 need the answer to it no one can figure it !

Find all the values of x that make 0.1x + 0.25(102 - x) < 17.10 true.

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)

What is the image of c for a 90° counterclockwise rotation about a? (3, 7) (-1, 3) (7, 3)