Find the domain and range of ƒ−1 given f(x)=x-9/21-4x

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

Divide. reduce the answer to lowest terms.5 2/3 ÷ 3 1/9

Is the square root of 4 plus the square root of 16 rational?