Question

20^3 - 13^3 - 7^3 What is the answer for this question use a^3-b^3-c^3 fomula

Answer 1

Step-by-step explanation:

here are mainy two forms to write the formula of a^3+b^3+c^3

First one is

a^3+b^3+c^3=(a+b+c)[a^2+b^2+c^2−ab−bc−ac]+3abc

Second one is

a^3+b^3+c^3=(a+b+c)1/2[(a−b)^2+(b−c)^2+(c−a)^2]+3abc

by method 1:-

that's why 20^3+(-13)^3+(-7)^3

= [(20+(-13)+(-7)][20^2+(-13)^2+(-7)^2-20(-13)-(-13)(-7)-20(-7)]+3•20•(-13)•(-7)

= [0][618+309]+5460

=0+5460

=5460

Answer 2

I think answer is 5080 using formula a^3 - b^3 - c^3