Question

​By using identity a² – b² = (a+b)(a-b), factorise 9x² – 4(y + 2x)².

Answer 1

Answer:

$(3x) {}^{2} - (2y + 4x) {}^{2} = (3x + 2y + 4x)(3x - 2y - 4x) = (7x + 2y)( - x - 2y)$