Interpret what P$(100)+$ P$\text{'}(100)=15000$ is if P$($x$)$ is the weekly profit

in dollars when x items are sold.

a$)$

$$15,000$ is the estimated total weekly profit when $101$ items are sold. $$15,000$ is the estimated total weekly profit when $100$ items are sold. $$15,000$ is the marginal profit when $101$ items are sold. $$15,000$ is the marginal profit when $100$ items are sold.

$3)$