Question

(5n- 3k)^2 -2(4n+6k)^2

Answer 1

$(5n- 3k)^2 -2(4n+6k)^2=25b^2-30kn+9k^2-2(16n^2+48kn+36k^2) =25n^2-30kn+9k^2-32n^2-96kn-72k^2=-7n^2-126kn-63k^2$