Question

$(2a + b) ^{3}$
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Answer 1

(2а+b)³=(2a)³+3*(2a)²*b+3*2a*b²+b³=

=8a³+12a²b+6ab²+b³

Answer 2

$\boxed {\; (x+y)^3=x^3+3x^2y+3xy^2+y^3=x^3+y^3+3xy(x+y)\; }\\\\\\(2a+b)^3=8a^3+3\cdot 4a^2\cdot b+3\cdot 2a\cdot b^2+b^3=8a^3+12a^2b+6ab^2+b^3=\\\\=8a^3+b^3+6ab(2a+b)$