Factorise fully this expression 2x^2+x-15

Aregression was run to determine if there is a relationship between hours of tv watched per day (x) and number of situps a person can do (y). the results of the regression were: y=ax+b a=-0.662 b=30.418 r2=0.703921 r=-0.839

Sum of the interior angles of a pentagon

Which best explains why this triangle is or is not a right triangle ?