In the following question, one or two equation(s) is/are given. You have to solve both the equations and find the relation between ‘x’ and ‘y’ and mark correct answer.

I. 8x4 – 18x2 + 4 = 0

II. 12y2 + 29y + 14 = 0

A x > y

B x ≥ y

C x < y

D x ≤ y

E x = y or the relation cannot be determined

Solution

Correct Answer: Option E

We will solve both the equations separately.

Equation I:

8x4 – 18x2 + 4 = 0

Let x2 = a

⇒ 8a2 –18a + 4 = 0

⇒ 8a2 – 16a – 2a + 4 = 0

⇒ 8a(a – 2) – 2(a – 2) = 0

⇒ (8a - 2)(a - 2) = 0

⇒ a = ¼ or a = 2

Since x = √a

∴ x = ±½= ±0.5 or,  x = √2 = ±1.41

Equation II:

12y2 + 29y + 14 = 0

⇒ 12y2 + 21y + 8y + 14 = 0

⇒ 3y(4y + 7) + 2(4y + 7) = 0

⇒ (3y + 2) (4y + 7) = 0

⇒ y = -2/3 = -0.67 or y = -7/4 = -1.75

Comparing the values of x and y, we get,

Few values of x are greater than y and few are smaller, same is true for y too. So, relation cannot be determined.

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