Question 246261
S = 5000 + 200x
D = 9500 - 100x


x is the price in dollars.
S is the supply
D is the demand


Looks like the supply goes up as the price goes up.


Looks like the demand goes down as the price goes up.


The graph of these equations would look like the following:


{{{graph(600,600,-10,30,-1000,19000,5000+200x,9500-100x)}}}


a) Graph the equations of the same coordinate system.


             b) What happens to the supply as the price increases?


The supply goes up.


             c) What happens to the demand as the price increases?


The demand goes down.


There's an equilibrium point where the supply is the same as the demand.


That's where the graph of the two equations intersect.


You solve for that point by making the two equations equal to each other.


You get:


5000 + 200x = 9500 - 100x


add 100x to both sides of this equation and subtract 5000 from both sides of this equation to get:


200x + 100x = 9500 - 5000


combine like terms to get:


300x = 4500


divide both sides of this equation by 300 to get:


x = 4500/300 = 45/3 = 15


the graph confirms that.