Answer
a) $y=6x+3000$
(b) The slope of $6$ means that each additional toaster oven produced adds $\$6$ to the weekly production cost.
(c) The $y$-intercept of $3000$ represents the overhead cost—the cost incurred without producing anything.
Work Step by Step
a) Let suppose, the denote number of toaster ovens produced in one week$=x$
The associated cost $=y$
By using graph points, $(1000,9000),~~(1500,12000)$ then,
We get an equation of line;
$y-9000=\frac{12000-9000}{1500-1000}(x-1000)$
$y=\frac{3000}{500}(x-1000)+9000$
$y=6(x-1000)+9000$
$y=6x-6000+9000$
$y=6x-3000$
(b) The slope of $6$ means that each additional toaster oven produced adds $\$6$ to the weekly production cost.
(c) The $y$-intercept of $3000$ represents the overhead cost—the cost incurred without producing anything.