a) ( - 6√2 )² - ( 5√3 )² =
= 36 x 2 - ( 5√3 )² =
= 36 x 2 - 25 x 3 =
= 72 - 25 x 3 =
= 72 - 75 =
= - 3
b) ( - 3√5)² + ( 2√2)² =
= 9 x 5 + ( 2√2 )² =
= 9 x 5 + 4 x 2 =
= 45 + 4 x 2 =
= 45 + 8 =
= 53
c) ( 5√3 )² - ( 2√7 )² =
= 25 x 3 - ( 2√7 )² =
= 25 x 3 - 4 x 7 =
= 75 - 4 x 7 =
= 75 - 28 =
= 47
