demand is downward sloping: P=-(2/7)Q +283/7 where P=price and Q= quantity of output

(73,20), (94,14) are points on the demand line

supply is upward sloping P=(1/5)Q + 2, (60,14) and (90,20) are points on the supply line

set them equal and solve for Q = about 79.12 at equilibrium output

substitute that into either equation and solve for P = about $17.82 for equilibrium price

plot the points and lines graphically. You can see equilibrium is between 14 and 20 for price

and between 73 and 90 for output. midway is about 17 and 81, an approximation, which is close