For this case we have the following polynomials:
 [tex]P = 3x ^ 2 + 2x - 6
Q = x + 5[/tex]
 By subtracting both polynomials we have:
 [tex]P - Q = (3x ^ 2 + 2x - 6) - (x + 5)
[/tex]
 What we must do is subtract terms of the same degree.
 We have then:
 [tex]P - Q = 3x ^ 2 + (2x - x) + (-6 - 5)
P - Q = 3x ^ 2 + x - 11[/tex]
 Answer:
 [tex]3x ^ 2 + x - 11[/tex] will be a polynomial