√1-x ≤4 решить неравенства помогите

[latex] \sqrt{1-x} \leq 4 \left \{ {{1-x \geq 0} \atop {1-x \leq 16}} \right. \left \{ {{x \leq 1} \atop {x \geq -15}} \right. [/latex] Ответ: x∈[-15;1]