The total cost $C(x)$, in dollars, to manufacture $x$ books is given by a linear function $C(x)=mx+b$, where $m$ is the variable cost per book and $b$ is the fixed cost. If the fixed cost is $200 and the total cost to manufacture 50 books is $450, what is the total cost, in dollars, to manufacture 800 books? (Disregard the $ sign when gridding your answer.)