ОЗД 1) 1-3х (под корнем) = 3+х 2) 21 (без корня) + 2х-7 (под корнем) =х 3) х=1 (без) + х+5 (под) 4) х=2-х(под)

1. [latex] \left \{ {{1-3x \geq 0} \atop {3+x \geq 0}} \right. [/latex]  [latex] \left \{ {{3x \leq1 } \atop {x \geq -3}} \right. [/latex] [latex] \left \{ {{x \leq \frac{1}{3} } \atop {x \geq -3}} \right. [/latex] Ответ:[-3;[latex] \frac{1}{3} [/latex]] 2. [latex]21-x= \sqrt{2x-7} [/latex] [latex] \left \{ {{21-x \geq 0} \atop {2x-7 \geq 0}} \right. [/latex] [latex] \left \{ {{x} \leq 21 \atop {x \geq \frac{7}{2} }} \right. [/latex] Ответ: [[latex] \frac{7}{2} [/latex];21] 3. [latex]x-1= \sqrt{x+5} [/latex] [latex] \left \{ {{x-1 \geq 0} \atop {x+5 \geq 0}} \right. [/latex] [latex] \left \{ {{x \geq 1} \atop {x \geq -5}} \right. [/latex] Ответ: [1;+∞] 4. [latex] \left \{ {{x \geq 0} \atop {2-x \geq 0}} \right. [/latex] [latex] \left \{ {{x \geq 0} \atop {x \leq 2}} \right. [/latex] Ответ: [0;2]