Ican't solve this question

The answer is 9

Step-by-step explanation:

Given that a = √3 + √2 and b = √3 - √2 . To be more easier, we do it one by one :

First, a² :

(√3 + √2)(√3 + √2)

= 3 + √6 + √6 + 2

= 5 + 2√6

Second, ab :

(√3 + √2)(√3 - √2)

= 3 - √6 + √6 - 2

= 1

Third, b² :

(√3 - √2)(√3 - √2)

= 3 - √6 - √6 + 2

= 5 - 2√6

Then, evaluate a² - ab + b² :

5 + 2√6 - 1 + 5 - 2√6

= 9

(Hope this can help)