Question

Спростіть вираз(7-4√5)(2+√5)^2(7+4√5)

Answer 1

$(7-4\sqrt{5})(2+\sqrt{5})^2(7+4\sqrt{5})=(49-16\cdot5)(2+\sqrt{5})^2=-31(2+\sqrt{5})^2=\\ \\ \\ =-31\cdot(4+4\sqrt{5}+5)=-31\cdot(9+4\sqrt{5})=-279-124\sqrt{5}$

Answer 2

I hope this helps you