Question

$x^{2} -9 x+14 \geq 0$

Answer 1

x1+x2=9 U x1*x2=14⇒x1=2 U x2=7
x∈(-∞;2] U [7;∞)

Answer 2

$x^{2} -9x+14 \geq 0 \\ (x-7)(x-2) \geq 0$

x ∈ ( - ∞; 2] ∨ [ 7;  + ∞)