Respuesta :

7.5% of $600 is $45

So instead of subtracting you add because its tax (keyword for add/multiply) 

So your answer is $645

Answer

Find out the  what is the total cost of the computer .

To proof

As given

a computer costs $600.00

sales tax rate is 7.5 percent .

7.5 % is written in decimal form

[tex]= \frac{7.5}{100}[/tex]

= 0.075

Sales tax on the computer cost = 0.075 × 600.00

                                                    = $45

Total cost of the computer = computer cost + sales tax cost

                                            =  600.00 + 45

                                           = $645.00

                                          = $645

Therefore total cost of the computer is $645 .

Hence proved