Answer:
Step-by-step explanation:
The given conditions allow us to write two equations. Let d and L represent the costs of the desktop and Laptop computers, respectively. Then we have ...
 L -d = 300
 .07L +.06d = 398
Multiplying the first equation by 0.06 and adding that to the second equation, we have ...
 .06(L -d) +(.07L +.06d) = .06(300) +(398)
 0.13L = 416
 L = 416/.13 = 3200
 d = 3200 -300 = 2900
The desktop computer cost $2900; the laptop computer cost $3200.