Question

the amount of revenue in dollars,y, that jason receives from selling x posters is given by the equation y=4x. the cost of producing x posters is given by the equation y= 1/2x +280. how many posters does jason need to sell so that the cost and revenue are equal?

Answer 1

If the revenue and cost are equal, then we get the equation:
$4x=1/2x+280$
Solving the above equation for x:
$4x-1/2x=280\\ (4-\dfrac{1}{2})x=280\\ \dfrac{7}{2}x=280\\ x=\dfrac{2}{7}\times280=80$
The number of posters does jason need to sell so that the cost and revenue are equal is 80. 

Answer 2

The problem gives that the Revenue = Cost of Production

y=4x
y=0.5x+280

4x=0.5x+280
3.5x=280
x=80

Jason need to sell 80 posters to break even. Revenue = Cost of production