Answer:
Cost of the computer before taxes is $1299.
Explanation:
Let the price of the computer before taxes is = $x
Tax rate on this computer = 7%
Therefore, computer cost including tax = (x + 7% of x)
=

= x + 0.07x
= $(1.07x)
Cost of the computer including tax is given as $1389.93.
Therefore, 1389.93 = 1.07x
x =

= $1299
Cost of the computer before taxes is $1299.