Answer
$ŷ =6992.1~dollars$
Work Step by Step
$ŷ =−36+11382x_1−613.2x_2−473.4x_3$
For a diamond with 0.85 carat, color E, clarity VVS1 and cut Excellent, that is $x_1=0.85$, $x_2=2$ and $x_3=3$:
$ŷ =−36+11382\times0.85−613.2\times2−473.4\times3=6992.1$
