Question

$\sqrt{x}$ +7=2 cum se face?

Answer 1

$\sqrt{x+7}=2\\ \\ Conditie de existenta: x+7 \geq0\Rightarrow x\geq-7 \Rightarrow D = [-7,+\infty)\\ \\ \sqrt{x+7}=2\Big|^2 \Rightarrow \Big(\sqrt{x+7}\Big)^2 = 4 \Rightarrow \underset{\overbrace{x+7\geq0}}{|x+7|} = 4 \Rightarrow x+7 =4 \Rightarrow \\ \\\\ \Rightarrow x = 4-7 \Rightarrow x = -3\in D \Rightarrow \boxed{S = \Big\{-3\Big\}}$