a+2√ab+4b (a+2√ab+4b)(√a-2√b) (√a)³ - (2√b)³
= = =
√a+2√b (√a+2√b)(√a-2√b) (√a)²- (2√b)²
(√a)³ - (2√b)³
=
a-4b
a+2√ab+4b (a+2√ab+4b)(√a-2√b) (√a)³ - (2√b)³
= = =
√a+2√b (√a+2√b)(√a-2√b) (√a)²- (2√b)²
(√a)³ - (2√b)³
=
a-4b