Разложите на множители: 1) 81c²-d²+9c+d; 2) a²+8ab+16²-1; 3) ax (6 маленькая) - 3x (6 маленькая) - ax³+3x³; 4) 25-m²-12mn-36n²:

1) 81c²-d²+9c+d = (9 с) ²-d²+9c+d = (9c-d) (9c+d) + (9c+d) = (9c+d) (9c-d+1) ;

2) a²+8ab+16-1 = a²+2*4ab+4²-1 = (а + 4b) ²-1 = (а + 4b - 1) (а + 4b+1) ;

3) ax⁶-3x⁶-ax³+3x³ = x³ (ax³-3x³-a+3) = x³ (x³ (a-3) - (a-3)) = x³ (x³-1) (a-3) ;

4) 25-m²-12mn-36n² = 25 - (36n²+12mn+m²) = 5² - (6n+m) ² = (5-6n-m) (5+6n+m).