Carcass wrote:
\(999,999^2-1\) equals:
(A) \((9^6)(11^6)\)
(B) \((10^6)(10^5 -2)\)
(C) \((10^6)(10^6 -2)\)
(D) \((10^5)^2\)
(E) \((10^6)^2\)
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITIONGRE - Math Book Key concept: \(x^2 - y^2\) is called a difference of squares, which can be factored as follows: \(x^2 - y^2= (x+y)(x-y)\)Likewise: \(999,999^2-1 = 999,999^2-1^2\)
\(= (999,999 + 1)(999,999 - 1)\)
\(= (1,000,000)(999,998)\)
\(= (1,000,000)(1,000,000 - 2)\)
\(= (10^6)(10^6 - 2)\)
Answer: C