Answer
$a.\quad 0.36x$
$ b.\quad$ No, the computer is selling at $ 36\%$ of its original price.
Work Step by Step
$a.$
$(x-0.4x)-0.4(x-0.4x)=(x-0.4x)(1-0.4)$
$=(0.6x)(0.6)$
$=0.36x$
$b.$
Using the result of part a,
$0.36=36\%,$
We conclude that the computer is selling at $ 36\%$ of its original price.
