Cost of producing and selling x tables is given by the function C(x)=50x+3000
x is the number of tables produced
Each table is sold for $70
So selling price of x tables S(x) = 70x
Now we find the number of table must be sold for the firm to break even
Break even occurs when selling price = cost price
That is S(x) = C(x)
70x = 50x + 3000
Subtract 50x on both sides
20x = 3000
x = 150
150 tables must be sold for the firm to break even