Below is a two-column proof incorrectly proving that the three angles of ΔPQR add up to 180°: Can someone please help me

What are the constants in this expression? -10.6+9/10+2/5m-2.4n+3m

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

Which represents the solution set of the inequality 5x-9 < 21? a. x < 12/5 b. x > 12/5 c. x > 6 d. x < 6