Question

(3a-b)(3a+b)+b^2
9x^2-(y+4x)(y-4x)
(5c-6d)(5c+6d)-25c^2
(7m-10n)(7m+10n)-100n^2

Answer 1

(3a) ²-b²+b²=9a²
9x²-y²+16x²=25x²-y²
25c²-36d²-25c²=-36d²
49m²-100n²-100n²=49m²-200n²