Factorize: x2−10x+21.
(x + 3) (x - 7)
(x - 3) (x - 7)
(x + 3) (x + 7)
(x - 3) (x + 7)
x2−10x+21=x2−7x−3x+21=x(x−7)−3(x−7)=(x−3)(x−7)
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