(7а-5b) (7а+5b) - (4a+7b){2}

Question

(7а-5b) (7а+5b) - (4a+7b){2}

Answer 1

(7a - 5b)(7a + 5b) - (4a + 7b)^2 = 49a^2 - 25b^2 - 16a^2 - 54ab - 49b^2 = 33a^2 - 74b^2 - 54ab 

Answer 2

49a^2-25b^2-16a^2+28ab+49b^2