Solve $-12x > 30$ when $x$ is a natural number.
A$\phi$ (empty set — no natural number satisfies it)
B$\{1, 2\}$
C$\{-3, -4, -5, \ldots\}$
D$\{0\}$
Answer & Solution
Correct answer: A. $\phi$ (empty set — no natural number satisfies it)
Divide by $-12$ (flip): $x < -30/12 = -5/2 = -2.5$.
Natural numbers are $\geq 1$, all positive. None can be less than $-2.5$. So the solution set is **empty**.
Over $\mathbb{Z}$, the solution would be $\{\ldots, -5, -4, -3\}$.
Related questions
Penalty for wrong answers : THERE WILL BE PENALTY FOR WRONG ANSWERS MARKED BY A CANDIDATE Penalty for wrong answers : THERE WILL BE PENALTY FOR WRONG ANSWERS MARKED BY A CANDIDATE For [[1,2],[2,4]], the determinant equals:If A is invertible, |A^{−1}| equals:For a 3 × 3 non-singular A with |A| = 5, the value of |adj A| is:For a non-singular square matrix A of order n, |adj A| equals:For non-singular A, B of the same order, (AB)^{−1} equals:For a non-singular A, (A^{−1})^{−1} equals: