Question

Expand:

`(3 - sqrt(8))^2`

Answer 1

Let’s expand:

`(3 - sqrt(8))^2`

Use the identity:

(a – b)² = a² – 2ab + b²

Let:

• a = 3
• `b = sqrt(8) = 2sqrt(2)`

Now expand:

= `3^2 - 2(3)(2sqrt(2)) + (2sqrt(2))^2`

= `9 - 12sqrt(2) + 4 xx 2`

= `9 - 12sqrt(2) + 8`

= `17 - 12sqrt(2)`