Hi, i need help on these quadratic questions, if you could please explain how to answer them with steps.

For what value of K will the graph of

y = 9x² + 3kx + k

have one x-intercept?

what are the x-coordinates where

f(x) = (x + 3)^2 +1

and

g(x) = 5 - 2x

intersect? Express the answer in simplified radicals.

Vladimir Guerrero Jr. hits a baseball and its height can be modeled by:

h(t) = 1.2 + 20t + 5t²

H is height in meters and T is time in seconds.

What is the maximum height of the ball and when will it get there?