Which of the following represents a constant from the expression given? \( 15 x^{2}+2 x+9 \) A. 15 B. 2 C. 24 D. 9

In the expression \( 15 x^{2} + 2 x + 9 \), the constant term is the number that does not have a variable attached to it. In this case, that would be 9, as it remains unchanged regardless of the value of \( x \). So, the answer is D. 9! Now, for some additional knowledge! The constant term in a polynomial represents the value of the polynomial when the variable \( x \) is equal to zero. Thus, substituting \( x = 0 \) into the expression will give you the value of the polynomial solely based on the constant term. Another fun fact: The degree of a polynomial is determined by the highest power of the variable present. Here, the term \( 15 x^{2} \) dominates with a degree of 2, classifying this polynomial as a quadratic. Quadratics have various applications in physics, engineering, and finance, often modeling parabolic trajectories and optimizing systems!