Упростите выражение:
1) (x + 2)(x + 11) − 2x(3 − 4x);
2) (a + 5)(a − 2) + (a − 4)(a + 6);
3) (y − 9)(3y − 1) − (2y + 1)(5y − 7);
4) (4x − 1)(4x − 3) − (2x − 10)(8x + 1).
$(x + 2)(x + 11) - 2x(3 - 4x) = x^2 + 2x + 11x + 22 - 6x + 8x^2 = (x^2 + 8x^2) + (2x + 11x - 6x) + 22 = 9x^2 + 7x + 22$
$(a + 5)(a - 2) + (a - 4)(a + 6) = a^2 - 2a + 5a - 10 + a^2 - 4a + 6a - 24 = (a^2 + a^2) + (-2a + 5a - 4a + 6a) + (-10 - 24) = 2a^2 + 5a - 34$
$(y - 9)(3y - 1) - (2y + 1)(5y - 7) = 3y^2 - 27y - y + 9 - (10y^2 + 5y - 14y - 7) = 3y^2 - 27y - y + 9 - 10y^2 - 5y + 14y + 7 = (3y^2 - 10y^2) + (-27y - y - 5y + 14y) + (9 + 7) = -7y^2 - 19y + 16$
$(4x - 1)(4x - 3) - (2x - 10)(8x + 1) = 16x^2 - 4x - 12x + 3 - (16x^2 - 80x + 2x - 10) = 16x^2 - 4x - 12x + 3 - 16x^2 + 80x - 2x + 10 = (16x^2 - 16x^2) + (-4x - 12x + 80x - 2x) + (3 + 10) = 0 + 62x + 13 = 62x + 13$
Пожауйста, оцените решение
