Question

Помогите пожалуйста дам много балов​

Answer 1

$\displaystyle\bf\\1)\\\\y=2x+3\\\\\boxed{D(y)=R}\\\\2)\\\\y=\sqrt{x+3} \\\\x+3\geq 0\\\\x\geq -3\\\\\boxed{D(y)=\Big[-3 \ ; \ +\infty\Big)}\\\\3)\\\\y=\sqrt{x-1} +\sqrt{5-x} \\\\\\\left \{ {{x-1\geq 0} \atop {5-x\geq 0}} \right. \ \ \ \Rightarrow \ \ \ \left \{ {{x\geq 1} \atop {x\leq 5}} \right. \ \ \ \ \Rightarrow \ \ \ \boxed{D(y)=\Big[1 \ ; \ 5\Big]}$