\(x^3-3x^2+3x+63=0\)

\(\Leftrightarrow x^3-3x^2+3x-1+64=0\)

\(\Leftrightarrow\left(x-1\right)^3+64=0\)

\(\Leftrightarrow\left(x-1\right)^3=-64\)

\(\Leftrightarrow x-1=-4\)

\(\Leftrightarrow x=-3\)

\(x^2-y^2=\left(x-y\right)\left(x+y\right)\)

???

\(\sqrt{2}\left(x-1\right)+\sqrt{8}=0\)

\(\Leftrightarrow\sqrt{2}\left(x-1\right)=-2\sqrt{2}\)

\(\Leftrightarrow x-1=-2\)

\(\Leftrightarrow x=-1\)

a, \(\left(7\sqrt{48}+3\sqrt{27}-2\sqrt{12}\right):\sqrt{3}\)

\(=\left(28\sqrt{3}+9\sqrt{3}-4\sqrt{3}\right):\sqrt{3}\)

\(=33\sqrt{3}:\sqrt{3}\)

\(=33\)

1

2 tấn 49 yến  =  249 yến

D