Pwease answer. This is missing work I have

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

Whats are the trickiest steps to do when adding or subtracting rational expressions? how does knowledge of rational numbers u in adding and subtracting rational expressions?

As a salesperson you get $50/day and $3.60/each sales you make.if you want to make $60 in one day, how many sales would you need need to make ? a 3b 4c 5d 6 show work.