Question

(x-3)^2=4

(x+4)^2=9

Cât este x la fiecare?

Answer 1

x-3=2...x=5

x-3=-2....x=1

S={1;5}

x+4=3.....x=-1

x+4=-3....x=-7

S={-7;-1}

Answer 2

$\it (x-3)^2=4\Leftrightarrow\sqrt{(x-3)^2}=\sqrt4\Leftrightarrow |x-3|=2\Leftrightarrow x-3=\pm2 \Leftrightarrow \\ \\ \Leftrightarrow x-3\in\{-2,\ 2\}|_{+3}\Leftrightarrow x\in\{1,\ 5{\}$