Объяснение:

[tex] {c}^{2} - {m}^{2} + 2 \times (c + m) {}^{2} = {c}^{2} - {m}^{2} + 2 \times( {c}^{2} + 2cm + {m}^{2} ) = {c}^{2} - {m}^{2} + {2c}^{2} + 4cm + {2m}^{2} = {3c}^{2} + {m}^{2} + 4cm[/tex]