Раскроем скобки:
(10x + 3y)(3y - 10x) - (7x - 8y)(7x + 8y)= 10x(3y) + 10x(-10x) + 3y(3y) + 3y(-10x) - 7x(7x) - 7x(8y) + 8y(7x) - 8y(8y)= 30xy - 100x^2 + 9y^2 - 30xy - 49x^2 - 56xy + 56xy - 64y^2= -100x^2 + 9y^2 - 49x^2 - 64y^2= -149x^2 - 55y^2
Ответ: -149x^2 - 55y^2.
Раскроем скобки:
(10x + 3y)(3y - 10x) - (7x - 8y)(7x + 8y)
= 10x(3y) + 10x(-10x) + 3y(3y) + 3y(-10x) - 7x(7x) - 7x(8y) + 8y(7x) - 8y(8y)
= 30xy - 100x^2 + 9y^2 - 30xy - 49x^2 - 56xy + 56xy - 64y^2
= -100x^2 + 9y^2 - 49x^2 - 64y^2
= -149x^2 - 55y^2
Ответ: -149x^2 - 55y^2.