Question

(4√m + 9√n)(4√m - 4√n)=

Answer 1

= 16m-16√mn+36√mn-36n= 16m+20√mn-36n

Answer 2

$(4sqrt{m}+9sqrt{n})(4sqrt{m}-4sqrt{n})=\\4sqrt{m}*4sqrt{m}+9sqrt{n}*4sqrt{m}+4sqrt{m}*(-4sqrt{n})+9sqrt{n}*(-4sqrt{n})=\\16m+36sqrt{mn}-16sqrt{mn}-36n=\\16m+20sqrt{mn}-36n$