Question

Without calculating the cubes find the value of (0.2)3-(0.3)3+(0.1)3

Answer 1

We can use the following to evaluate this:

a^3 - b^3 - c^3 - 3abc = (a + b + c)( a^2 + b^2 + c^2 - ab - bc - ca)

a^3 - b^3 - c^3 = (a + b + c)( a^2 + b^2 + c^2 - ab - bc - ca) + 3abc

Hope this helps.