\(\sqrt{31-12\sqrt{3}}+\sqrt{31+12\sqrt{3}}\)

=\(\sqrt{\left(3\sqrt{3}\right)^2-2.3\sqrt{3}.2+4}+\sqrt{\left(3\sqrt{3}\right)^2+2.3\sqrt{3}.2+4}\)

=\(\sqrt{\left(3\sqrt{3}-2\right)^2}+\sqrt{\left(3\sqrt{3}+2\right)^2}\)

=\(3\sqrt{3}-2+3\sqrt{3}+2=6\sqrt{3}\)

ket truyen lao hac, co be ban diem va cu Bo-men chet. cai chet cua moi nhan vat de lai trong long nguoi doc nhujng bai hoc