(63√2−4√13)2
( 6∛2 - 4√13)^2 =
( 6∛2 - 4√13) ( 6∛2 - 4√13) =
36∛4 - 24*√13*∛2 - 24*√13*∛2 + 16*13 ) =
36∛4 - 48*√13*∛2 + 208
how'd you get 208 ?
When you multiply the "last" terms, you get.....
-4√13 * -4√13 = 16 * √13 * √13 = 16 * √132 = 16 * 13 = 208
