Find the vertex, the axis of symmetry, and the y intercept of the graph

An arrow is shot vertically upward at a rate of 180ft/s. use the projectile formula h=−16t2+v0t to determine at what time(s), in seconds, the arrow is at a height of 420ft. round your answer(s) to the nearest tenth of a second.

For f(x)=2x+3 and g(x)=x^2- 8 find (f+g) (x)

What are the exclude value of mn+3m