(9c^2 + d^2)(3c – d)(3c + d); (5x^4 – 7y^2)(5x^4 + 7y^2)

Question

(9c^2 + d^2)(3c – d)(3c + d);

(5x^4 – 7y^2)(5x^4 + 7y^2)

Answer 1

1) (9c²+d²) (9c²-d²) = (81c^4-d^4)
2) (25x^9-49y^4)