Question

Can someone help answer these questions thank you !

Answer 1

Explanation:

4) (a - b)² = a² - 2ab + b²

`(5-√(5))^(2)=5^(2)-2*5*√(5)+(√(5))^(2)\\\\ =25-10√(5)+5\\\\=30-10√(5)`

5) Use FOIL method.

`(1+√(2))(3-√(2))=(1*3)+1*(-√(2))+√(2)*3+√(2)*(-√(2))\\\\ =3-√(2)+3√(2)-2\\\\=3-2-√(2)+3√(2)\\\\=1-2√(2)\\`