bjr
• (2√2 - 3)² = [on utilise (a - b)² = a² - 2ab + b² ]
(2√2)² - 2*2√2*3 + 3² = (* = fois)
2²(√2)² - 12√2 + 9 = [ (√2)² = 2 ]
8 - 12 √2 + 9 =
17 - 12√2
• (√6 + 2)(√3 - √2) = (double distributivité)
√6 √3 - √6√2 + 2√3 - 2√2 = [ √6 = √(2*3) = √2√3 ]
√2√3√3 - √3√2√2 + 2√3 - 2√2 =
3√2 - 2√3 + 2√3 - 2√2 =
(3 - 2)√2 =
√2
A = 17 - 12√2 + √2
A = 17 - 11√2
