Поманите пж. (Там 10 примеров )

1.
$4x(x - 5y + c) = {4x}^{2} - 20xy + 4cx$
2.
$- 6a(a - 3b + 2) = { - 6a}^{2} - 18ab - 12a$
3.
$5y(y + 5x - 4) = {5y}^{2} + 25xy - 20y$
4.
$5(a + 2) + (a + 2) = 5a + 10 + a + 2 = 6a + 12$
5.
$x(x - 7) - 3a(x - 3) = {x}^{2} - 7x - 3ax + 9a$
6.
$7a(a - 7) - 3a(a - 3) = {7a}^{2} - 49a - {3a}^{2} + 9a = {4a}^{2} - 40a$

7.
$2x(x + 1) - 4x(2 - x) = {2x}^{2} + 2x - 8x + {4x}^{2} = {6x}^{2} - 6x$
8.
$2y(2x - 3y) - 3y(5y - 3x) = 4xy - {6y}^{2} - {15y}^{2} + 9xy = 13xy - {21y}^{2}$
9.
$15(8x - 1) - 8(15x + 4) = 120x - 15 - 120x - 32 = - 47$
10.
$4(2 - 3x) + 7(6x + 1) - 9(9x + 4) = 8 - 12x + 42x + 7 - 81x - 36 = - 21 - 51x$