Me with 1 of 3 problems of absolute value functions

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

F(x)=x/2-2 and g(x)=2x^2+x-3 find (f+g)(x)

In right ∆abc shown below, the midpoint of hypotenuse ac is located at d and segment bd is drawn. if ab = 12 and bc = 16, then explain why bd = 10. hint: consider what you know about the diagonals of a rectangle.