Question

упростите выражение (x - y)(2x-3y)-(3x-y)(2x+y);
(2a+3)(2a+3)-(2a+1)(2a-1); (3c - d)(d+3c)+(4c-d)(c-4d)

Answer 1

1) 2x^2 - 5xy + 3y^2 - ( 6x^2 + xy - y^2) = 2x^2-5xy+3y^2-6x^2-xy+y^2 =
= - 4x^2  - 6xy + 4y^2
2) (2a + 3)^2 - ( 4a^2 - 1) = 4a^2 + 12a + 9 - 4a^2 + 1 = 12a + 10
3) 9c^2 - d^2  + 4c^2 - 16cd - cd + 4d^2 = 13c^2- 17cd + 3d^2