Solve for x plz show all the work. x/3=6

The table below shows the height of a ball  x  seconds after being kicked.  what values, rounded to the nearest whole number, complete the quadratic regression equation that models the data? f(x)  =  x2  +  x  +  0based on the regression equation and rounded to the nearest whole number, what is the estimated height after 0.25 seconds?   feet

How do u write a function for the reflection across the y axis

Based on the diagrams, what is the value of x?