A certain electronics manufacturer found that the average cost C to produce x game systems can be found using the equation:
C = 0.03x²-6x+900

What is the minimum average cost per system and how many
game systems should be built in order to acheive that minimum?
The minimum average cost is:___

The number of game systems that should be build to acheive the minimum is:____
**Answer both to the nearest whole number.