In the equation y = mx + b, what does m denote?

• A. Intercept
• B. Slope
• C. Concentration
• D. Absorbance

Answer: (B)

The key idea is the slope of a straight line. In y = mx + b, the slope m tells you how much y changes for each unit increase in x. It sets the line’s steepness and reflects the sensitivity of y to changes in x—for example, if x represents concentration and y a signal, m is the signal change per unit concentration. The intercept b is the y-value when x is zero, not the rate of change. The options concentration and absorbance are the variables themselves, not the rate at which y changes with x.