OG详解-OG4 数学2 Q14

The correct answer is 2. It’s given that function f is defined by f (x)= 2x + 3. Therefore, the equation representing the graph of y = f (x) in the xy-plane is y = 2x + 3, and the graph is a line. For a linear equation in the form y = mx + b, m represents the slope of the line. Since the value of m in the equation y = 2x + 3 is 2, the slope of the line defined by function f is 2. It’s given that line j is parallel to the line defined by function f. The slopes of parallel lines are equal. Therefore, the slope of line j is also 2.