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Determine rate of change from an equation

The rate of change in a linear relationship is the constant change in the dependent variable for each one-unit change in the independent variable, represented by the coefficient of xx when the equation is written as y=mx+by=mx+b, including negative or fractional coefficients. It determines the line’s direction and steepness and carries units, whereas bb represents the initial value or yy-intercept; nonlinear equations, variable rates, and more advanced equation forms are outside this scope.

Detailed Explanation: Determine rate of change from an equation

To find the rate of change, write the equation in the form

y=mx+by=mx+b

The coefficient mm of xx is the rate of change. It tells how much yy changes when xx increases by 1. The number bb is the starting value, not the rate of change.

Example: Find the rate of change in

y=12x+6y=-\frac{1}{2}x+6

Step 1: Identify the coefficient of xx.

The coefficient of xx is

12-\frac{1}{2}

So, the rate of change is

12\boxed{-\frac{1}{2}}

Step 2: Interpret the rate.

For every increase of 1 in xx, the value of yy decreases by 12\frac{1}{2}.

The negative sign means the relationship is decreasing. The 66 is the initial value, or yy-intercept, not the rate of change.

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