Question

решите уравнения
3х²-21=0

Answer 1

3х^2=21
х^2=7
х=+- корень из 7

Answer 2

$3x^2-21=0\\ \\ 3x^2 = 21 \\ \\ x^2 = 21:3 \\ \\ x^2 = 7 \\ \\ x = б\sqrt{7}; \\ \\ \\ \boxed{\boldsymbol{OTBET: б\sqrt{7}}}$