Consider a perfectly competitive market described by the supply function p = 20 + 0.1q and demand function p = 80 - 0.3q. if the market is in equilibrium,

Then they are equal to each other

set them eual to eachother

20+0.1Q=80-0.3Q
addd0.3Q to both sides
20+0.4Q=80
subtract 20
0.4Q=60
divide by 0.4
Q=150
subsiut to find P
20+0.1Q=P
20+0.1(150)=P
20+15=P
35=P

P=35
Q=150