Given that: (5x − 3)3 + (2x + 5)3 + 27(4 - 3x)3 = 9(3 - 5x)(2x + 5)(4 - 3x), then the value of (2x + 1) is?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 15
Trick:
It is of the form : a³ + b³ + c³ = 3abc
In this type of form, a + b + c = 0
Now,
(5x - 3) + (2x + 5) + 3(4 - 3x) = 0
5x - 3 + 2x + 5 + 12 - 9x = 0
⇒ 2x = 14
⇒ x = 7
So,
2x + 1 = 2(7) + 1 = 14 + 1 = 15