Please guys help

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

What is the result of adding the system of equations? 2x+y=4 3x-y=6

4+(2+x) can you me solve this problem