bjr
(x - √2)(x + √2) + 2(√2 x + 2) = ( (a - b)(a + b) = a² - b² )
x² - (√2)² + 2√2 x + 4 = ( (√2)² = 2 )
x² - 2 + 2√2 x + 4 =
x² + 2√2 x + 2