Answer
$ŷ =57.79$
Work Step by Step
$ŷ =84.04-0.87x_1-0.51x_2-0.45x_3+0.33x_4$
If confidence score = 25, computer knowledge = 19, computer liking = 20 and trait anxiety = 43, that is, $x_1=25$, $x_2=19$, $x_3=20$ and $x_4=43$:
$ŷ =84.04-0.87\times25-0.51\times19-0.45\times20+0.33\times43=57.79$
