X=D(p)=400-p
The equation X = D(p) = 400 - p represents a linear function. In this equation, X refers to a dependent variable, and p refers to an independent variable.
To find the value of X for a specific value of p, simply replace p with the desired value and solve the equation.
For example, if you want to find the value of X when p = 100, substitute p = 100 into the equation:
X = 400 - (100)
X = 400 - 100
X = 300
Therefore, when p = 100, X = 300.
You can use this equation to find any value of X for a given value of p.