Simplify it? (a+3)³+(a-3)³

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Answer 1 · 2018-05-15T15:34:50

#color(magenta)(=>18a^2+27#

#color(magenta)(=>9(2a^2+3)#

Using the identities:

#color(red)((a+b)^3= a^3+3a^2b+3ab^2+b^3#

#color(red)((a-b)^3=a^3-3a^2b+3ab^2-b^3#
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We get: #(a+3)^3+(a-3)^3#

#=>(a^3+3a^2*3+3a(3)^2+(3)^3)-(a^3-3a^2*3+3a(3)^2-(3)^3)#

#=>cancel(a^3)+9a^2+cancel(3a*9)+27-cancel(a^3)+9a^2-cancel(3a*9)+27#

#color(magenta)(=>18a^2+27#

#color(magenta)(=>9(2a^2+3)#

~Hope this helps! :)