Question

The number of real solutions of x 7 + 5 x 3 + 3 x + 1 = 0 is equal to ______.

• A. 0
• B. 1
• C. 3
• D. 5

Answer 1

Answer: (B)

1

Answer 2

The correct answer is (B) : 1

Fig. Functions

$ƒ′(x) = 7x^6 + 15x² + 3 > 0 ∀x ∈ R$
f(x) is always increasing.
So clearly, it intersects the x-axis at only one point.