Question

Choose two values, a and b, each between 8 and 15. Show how to use the identity a^3+b^3=(a+b)(a^2-ab+b^2) to calculate the sum of the cubes of your numbers without using a calculator

Answer 1

`\large \boxed{\sf \ \ 9^3+10^3=1729 \ \ }`

Explanation:

Hello, I choose 9 and 10, so I can write

`9^3+10^3=(9+10)(9^2-9*10+10^2)=(10+9)(81-90+100)=10*91+9*91=910+819=1729`

Hope this helps.

Do not hesitate if you need further explanation.

Thank you