Answer
$23.2$ million tablet PCs are expected to be sold in 2018.
Work Step by Step
To find the value of $x$, find the difference of $2018$ and $2000$
$x=2018-2000=18$
$x=18$
Now substitute the value of $x$ into the given equation to find the number of expected tablet PCs (in millions) to be sold in the year 2018.
$-1.7x^{2}+49x-308$
$=-1.7(18)^{2}+49(18)-308$
$=-1.7(18\times18)+882-308$
$=-1.7(324)+882-308$
$=-1.7(324)+882-308$
$=-550.8+882-308$
$=331.2-308$
$=23.2$
$23.2$ million tablet PCs are expected to be sold in 2018.
