Market research has shown that at a price of $230, 100 number of plasma TV’s are sold and if the price is reduced to $190, then 200 number of TV’s are sold. Find the equation that represents this demand curve and state in the form of p=mx+b (Slope Intercept Form of a Linear Equation).

Question

Market research has shown that at a price  of $230, 100 number of plasma TV’s are sold and if the price is reduced to $190, then 200 number of TV’s are sold.  Find the equation that represents this demand curve and state in the form of p=mx+b (Slope Intercept Form of a Linear Equation).

anonymous · Answer

p=mx+b
is p the price?
if yes, plug the numbers and you'll get two equations
230 = 100m + b   and
190 = 200m + b     
solve those equations, you'll get m = -2/5 and b=270
so the equation is
p = -(2/5)x + 270

to check whether this equation is right or not, plug the (100,230) or (200,190)