Suppose the equation for a market demand curve

Question

is QD = 15 − 0.2P and the equation for a market supply curve is Qs = −3+ 0.4P

Answer 1

so you want the intersection?

15 - .2 p = -3 + .4 p

.6 p = 18

p = 180/6 = 30
q = -3+12 = 9

Answer 2

O=25;Q=10