1. x - 1 / x = 2
atunci x² - 2 · x · 1 /x + 1 / x² = 4
= - 2
x² + 1 / x² = 4 + 2 = 6
2. a - b = 1
a² - 2ab + b² =1
( a² + b² - 2ab ) + 2· ( a - b) + 1 = 1 + 2 + 1 = 4
=1 =1
3 . a · ( c + d) + b · ( c +d ) =4√3
( c + d) · ( a + b) = 4√3
= 4
c + d = √3