If (x2+3x+5)(x2−3x+5)=m2−n2, then m= ________.
The factors of x4 + x2 + 25 are (a) (x2 + 3x + 5) (x2 − 3x + 5) (b) (x2 + 3x + 5) (x2 + 3x − 5) (c) (x2 + x +5) (x2 − x + 5) (d) none of these