Question

The expansion of  〖(5y+ 1/3)〗^3  is  125y^3 + _________________ + 1/27 (1 Point) a) 25y^2 + 5y/3 b) 25y^2 + 25y/9 c) 25y + 5/9 d) none of these​

Answer 1

Step-by-step explanation:

Formula used: if a+b+c=0, then a3+b3+c3=3abc

125(x−y)3+(5y−3z)3+(3z−5x)3=(5x−5y)3+(5y−3z)3+(3z−5x)3

Now, (5x−5y)+(5y−3z)+(3z−5x)=0

⇒(5x−5y)3+(5y−3z)3+(3z−5x)3=3(5x−5y)(5y−3z)(3z−5x)

                                                                               =15(x−y)(5y−3z)(3z−5x)

∴125(x−y)3+(5y−3z)3+(3z−5x)3=15(x−y)(5y−3z)(3z−5x)