[tex](x {}^{2} - 2x) {}^{2}[/tex]
[tex](x { }^{2} ) {}^{2} - 2x {}^{2} \times 2x + (2x) {}^{2} [/tex]
[tex](x {}^{2} ) {}^{2} =x {}^{4} [/tex]
[tex] - 2x {}^{2} \times 2x[/tex]
[tex] - 4x {}^{2} \times x {}^{1} = - 4x {}^{3} [/tex]
[tex](2x) {}^{2} \times {}^{2} = 4x { }^{2} [/tex]
[tex]x {}^{4 } - 4x {}^{3} + x4 {}^{2} [/tex]