Выполните умножение a) (2t-v+s) (t+2v-s) б) (a+2b+3c) (2a-b+2c)

A) (2t-v+s) (t+2v-s) = 2t^2 - tv + ts + + 4tv-2v^2 + 2vs - 2ts + sv - s^2 = = 2t^2 + 3tv - ts + 3vs - 2v^2 - s^2

б) (a+2b+3c) (2a-b+2c) = 2a^2 + 4ab + + 6ac - ab - 2b^2 - 3bc + 2ac + 4bc + 6c^2 = 2a^2 - 2b^2 + 6c^2 + 3ab + 8ac + bc