Question

Expand and simplify (2V5 + 1)(3V5 - 1)

Answer 1

`29+√(5)`

Explanation:

Let
`√(5) = a` for simplicity. now our equation is

(2a+1)(3a-1)

now expand

2a*3a-2a+3a-1 = 6a^2+a-1

remember that
`√(5) = a`

thus we get
`6√(5)^2+√(5)-1 = 6(5)-1+√(5)=30-1+√(5)=29+√(5)`