The equation "y = 2x + 3" represents a linear function, where y is the output value, x is the input value, and the numbers 2 and 3 are constants. The number 2 is the slope, indicating that for every increase of 1 in x, y increases by 2. The number 3 is the y-intercept, meaning that when x is 0, y equals 3. This equation can be graphed on a coordinate plane, resulting in a straight line. The slope determines the steepness of the line, while the y-intercept shows where the line crosses the vertical axis. This function is commonly used in various fields, including mathematics and economics.