\[\boxed{\text{841\ (841).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ (c + 2)(c - 3) - (c + 1)(c + 3) =\]
\[= - 5c - 9\]
\[2)\ (p + 4)(p - 11) + (p + 6)^{2} =\]
\[= 2p^{2} + 5p - 8\]
\[3)\ 3 \cdot (x - 5)^{2} - \left( 8x^{2} - 10x \right) =\]
\[= 3 \cdot \left( x^{2} - 10x + 25 \right) - 8x^{2} + 10x =\]
\[= 3x^{2} - 30x + 75 - 8x^{2} + 10x =\]
\[= - 5x^{2} - 20x + 75 =\]
\[= - 5 \cdot \left( x^{2} + 4x - 15 \right)\]
\[4)\ 7 \cdot (2y - 5)^{2} - 2 \cdot (7y - 1)^{2} =\]
\[= - 70y^{2} - 112y + 173\]