Question 20
If $$A = 125$$ and $$B = 8$$, then what is the value of
$$(A + B)^3 - (A - B)^3 - 6B(A^2 - B^2)$$?
Solution
$$(A+B)^3-(A-B)^3-6B(A^2-B^2)$$
$$=\left(A+B-A+B\right)^3+3\left(A+B\right)\left(A-B\right)\left(A+B-A+B\right)-6B\left(A^2-B^2\right).$$
$$=\left(2B\right)^3+6\left(A^2-B^2\right)B-6B\left(A^2-B^2\right).$$
$$=\left(2\times8\right)^3=4096.$$
A is correct choice.
Get AI Help?
Create a FREE account and get:
- Free SSC Study Material - 18000 Questions
- 230+ SSC previous papers with solutions PDF
- 100+ SSC Online Tests for Free
