1)(3-√13)⋅(3+√13)= 2)3√5-√80+31√20=

Question

1)(3-√13)⋅(3+√13)=
2)3√5-√80+31√20=

Answer 1

1) (3-√13)·(3+√13)=3²-(√13)²=9-13=-4
2) 3√5-√80+31√20=3√5-4√5+62√5=√5·(3-4+62)=61√5