Question

simplify : (x-2/5y)^3 - (x+2/5y)^3​

Answer 1

Answer:

Step-by-step explanation:

Let z= (x-2/5y)^3 - (x+2/5y)^3​

Let 2/5y=a

z=(x-a)³-(x+a)³

=(x-a-x-a)[ (x-a)²+(x+a)²+(x-a)(x+a)]

=-2a(2x²+2a²+x²-a²)

=-2a(3x²+a²)

putting value of a

=-2*2/5y(3x²+4/25y²)

=-4/5y(3x²+4/25y²)