Question

simplify
$(4x + \sqrt{5y} ) \times (4x - \sqrt{5y} )$
No silly answer

Answer 1

$(4x + \sqrt{5y} ) \times (4x - \sqrt{5y} ) \\ as \\ (x + y)(x - y) = {x}^{2} - {y}^{2} \\ = {(4x)}^{2} - {( \sqrt{5y} )}^{2} \\ = 16 {x}^{2} - 5y$

Answer 2

$(4x+ \sqrt{5y} ) \times (4x - \sqrt{5y}) \\ \\ This \:\: is \:\: in \:\: the \:\: form \:\: of \:\: (a+b) \times (a-b) = a^{2} - b^{2} \\ \\ = (4x)^{2} - (\sqrt{5y})^{2} \\ \\ = 16x^{2} - 5y \\ \\ hope \:\: it \:\: helps...$