How do you multiply #(2x+5)^3#?

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Answer 1 · 2015-04-07T12:52:09

If there is #(a+b)(c+d)# then:

#(a+b)(c+d) = a*c + a*d + b*c +b*d#

#(2x+5)^3 = (2x+5) * (2x+5) * (2x+5)#

#= [4x^2 + 10x + 10x +25] * (2x+5)#

If there is #(a+b+c)(d+e)# then:

#(a+b+c)(d+e) = ad+ae+bd+be+cd+ce#

#= (4x^2 + 20x + 25) * (2x+5)#

#=8x^3 + 20x^2 + 40x^2 + 100x + 50x + 125#

The answer is:

#=8x^3 + 60x^2 + 150x + 15#