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.


a = 8 and b = 10

Answer 1

@AZ

Answer 2

All you have to do is replace the numbers with a and b and simplify it

\(\color{red}{a}^3 + \color{orange}{b}^3 = (\color{red}{a} + \color{orange}{b})(\color{red}{a}^2 - \color{red}{a}\color{orange}{b} + \color{orange}{b}^2) \)

so you said a = 8 and b = 10

\(\color{red}{8}^3 + \color{orange}{10}^3 = ??\)

Answer 3

ok

8^3+10^3 = (8+10)(10^2 − (8)(10) +8^2)

Answer 4

this?

Answer 5

yes

Answer 6

sooo...

(18)(100 − 80 + 64)

am I correct?

Answer 7

yes

Answer 8

and when I do 18 x 64, I will get my final answer, correct?

Answer 9

im just gonna assume im correct

ty for helping :D

Answer 10

Yup! Good job :)

Answer 11

ok ty

Answer 12

yw