The answer is C.
When a positive and negative number are multipled or divided, the result is negative.
To determine the minimum of an equation, we derive the <span>equation using differential calculus twice (or simply </span><span>take the second derivative of the function). If the </span><span>second derivative is greater than 0, then it is minimum; </span><span>else, if it is less than 1, the function contains the </span><span>maximum. If the second derivative is zero, then the </span><span>inflection point </span><span>is</span><span> identified.</span>
The greatest common factor between 72 and 54 is 18.