Eis the midpoint of df, de= 2x+4 and ef = 3x-1 find de,ef,df

Since E is the midpoint of DF, then DE = EF, so...
2x+4 = 3x-1 Subtract 2x from both sides.
4 = x-1 Add 1 to both sides.
x = 5
DE = 2x+4 Substitute x = 5.
DE = 2(5)+4
DE = 14

EF = 3x-1 Substitute x = 5.
EF = 3(5)-1
EF = 14

DF = 14+14
DF = 28.

First, plot quantity demanded. This will be your demand curve. You do that like this: you see that at the price 4.89, quantity demanded was 311. Plot a point at the coordinates x:311, y:4.89. Same for other prices; plot the 4 other points (for example, the second has coordinates x:388, y:4.29). Now connect those points with a curve. This is your demand curve! Now plot quantity supplied the same way and draw the supply curve. 
Surplus is when quantity supplied is greater than quantity demanded. This happened at prices 5.39 and 5.19. Shortage is when quantity demanded is greater than quantity supplied, which happened at prices 4.29 and 4.89. Equilibrium is when both quantities are the same and the market clears; that happened at the price 5.00.