Question

-5 is a root of 2x square +px-15 find p.

Answer 1

if -5 is the root of the given quadratic  2 x² + p x - 15  then  x+5 is a factor.  Then  if we substitute -5 in place of x, we get zero as the value of quadratic.

     2 (-5)² + p (-5) - 15 = 0
     35 - 5 p = 0
     p = 7