Question

1. Find the cube of
(i)(a + 2b)​

Answer 1

Answer:

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Step-by-step explanation:

( 1+ a-2b ) ^3 = ( 1+a) ^3 -(2b) ^3 - 3*(1+a) *(2b) ( 1+a-2b)

= (1+a) ^3 - 8b ^3 -( 6b -6ab )( 1+a- 2b)

= ( 1+a) ^3 -8b^3 - ( 6b + 6ab- 12b^2 -6ab -6a^2 b -12 a b ^2)

= ( 1+a)^3 - 8b^3 - 6b -6ab +12 b^2 + 6ab + 6 a^2*b + 12 a*b ^2

= 1+ a^3 + 3a + 3a^2 -8b^3 -6b -6ab + 12b^2 + 6ab + 6a^2 b + 12 a*b ^2