SSC CHSL 2021 PYQ — Question 60

The correct answer is Option 4 i.e. ${{7} \over 2}$.

Given:

  $({{4x-5}})^3+$$({{x-2}})^3+$ $27({{2x-5}})^3=9(4x-5)(x-2)(2x-5)$ 

Concept USed:

a³ + b³ + c³ = 3abc, then 

a + b + c = 0

Explanation:

According to the given question:

a = (4x - 5), b = (x - 2) and c = 3(2x - 5)

Now, putting these values, we get

(4x - 5) + (x - 2) + (6x - 15) = 0

⇒ 11x - 22 = 0

⇒ x = 2

Now, required value = $(2+{{3} \over 2})$ = $7 \over 2$

Hence the required answer is $7 \over 2$.