Question

factorise 27y3+125y3

Answer 1

27y3+125y3=(3y)3+(5y)3
                    =(3y+5y)(9y2+25y2-15y2)

Answer 2

$27y^{3} + 125y^{3}$
  = $(3y)^{3} + (5y)^{3}$
 Using Formula, $a^{3} + b^{3} = (a + b) (a^{2} - ab + b^{2})$
       $(3y)^{3} + (5y)^{3}$  =(3y + 5y) {$(3y)^{2} - 3y*5y - (5y)^{2}$}                                             = $9y^{2} + 15y^{2} - 25y^{2}$
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