Question

упростите выражение
1) (7x-8y)(7x+8y)-40x^2+68y^2
Ответ :4y^2

Answer 1

49x^2-64^y-40x^2+68y^2=9x^2

Answer 2

49x^2 + 56xy - 56 xy - 64y^2 - 40 x^2 +68y^2= 9x^2+4y^2