ОТВЕТ: x∈ (5,6)

X² - 11x + 30 ≤0
X² - 5x - 6x + 30 ≤0
X(x-5) -6(x-5) ≤0
(x-5)(x-6)≤0

[tex]\left \{ {{x-5\leq 0} \atop {x-6\geq0}} \right.[/tex]

[tex]\left \{ {{x-5\geq 0} \atop {x-6\leq 0}} \right.[/tex]

[tex]\left \{ {{x\leq 5} \atop {x\geq 6}} \right.[/tex]

[tex]\left \{ {{x\geq 5} \atop {x\leq 6}} \right.[/tex]

находим пересечение

x∈ (5,6)