Multiple Choice Mathematics: Strategic Answer Selection Process

Let's solve the problem by recognizing how the slope influences a linear function:

• Recall the form of a linear function: $y = mx + b$.
• The slope $m$ defines the inclination of the line:
  • Positive slope ($m > 0$): Function increases as $x$ increases.
  • Negative slope ($m < 0$): Function decreases as $x$ increases.
  • Zero slope ($m = 0$): Function is constant, forms a horizontal line.

Given the question is about a negative slope, we focus on the behavior when $m < 0$. In such a case, as $x$ increases, the value of $y$ decreases. This is because the line slopes downward from left to right.

Therefore, with a negative slope, the graph of the linear function is decreasing.

Hence, the correct answer is Choice 3: If the slope is negative then the function is decreasing.