Question 5322
 x=3 and x=-5, 
when x =3
then x-3 =0  --- eq1
when x=-5
then x+5 =0    ----eq2
as the two equation gives 0 result then their multiplication must give 0 result
so (x-3) * (x+5) =0   (* sign indicate multiplication)
or x^2+5x-3x -15 =0     ( by expanding and multiplying the left hand side)
or x^2+2x-15 =0
this is the required answer  (arun_662002@yahoo.co.in)