Выполните действия: (x-5) (5+x) ;

(8+y) (y-8) ;

(10-k) (k+10) ;

(a+2/4b) (a-2/3b) ;

(4/9x-y) (y+4/9x) ;

(4/15n-m) (m+4/15n) ;

(9x-5y) (9x+5y) ;

(-4a+3b) (3b+4a) ;

(13k-2d) (2d+13k) ;

(5/4c+3/7d) (3/7d-5/4c) ;

(1/3x-3y) (3y+1/3x) ;

(1/5a+1/9b) (1/9b-1/5a).

1) (x-5) (x+5) = x²-25

2) (8+y) (y-8) = y²-64

3) (10-k) (k+10) = 100-k²

4) (a+2/4b) (a-2/4b) = a²-4/16b = a²-1/4b

5) (4/9x-y) (y+4/9x) = 16/81x²-y²

6) (4/15n-m) (m+4/15n) = 16/225n²-m²

7) (9x-5y) (9x+5y) = 81x²-25y²

8) (-4a+3b) (3b+4a) = (3b-4a) (3b+4a) = 9b²-16a²

9) (13k-2d) (2d+13k) = 169k²-4d²

10) (5/4c+3/7d) (3/7d-5/4c) = 9/49d²-25/16c²

11) (1/3x-3y) (3y+1/3x) = 1/9x²-9y²

12) (1/5a+1/9b) (1/9b-1/5a) 1/81b²-1/25a²