bjr
• (√15 + √10)² = (√15)² + 2√15√10 + (√10)²
= 15 + 2√(3 x 5) √(2 x 5) + 10
= 15 + 10 + 2√3√5√2√5
= 25 + 2√5√5√3√2 [√5√5 = 5 ; √3√2 = √6 ]
= 25 + 2*5*√6
= 25 + 10 √6
• (√15 + √10)² - 10√6 = 25 + 10√6 - 10√6
= 25
• √[ (√15 + √10)² - 10√6 ] = √25 = 5
