The answer to the question is 9±√21/2
By using the quadratic formula x=-b±√b²-4ac/2a
By comparing x²-9 x+15=0 with ax²+bx+c
we get a=1 b=-9 c=15
x=-(-9)±√(-9)²-4×1×15/2×1
x=9±√81-60/2
x=9±√21/2
So the answer to the question is x=9+√21/2
and x=9-√21/2
Learn more about quadratic formula here:https://brainly.com/question/1214333
#SPJ4