Then two types can be listed:
( 1) 0.5x-y=-20
(2) 0.8x-y=40
The two formulas are subtracted to get x=200 (that is, the price tag).
Substitute the value of x into any formula and calculate the cost y= 120.
2. Set the maximum discount of Z to ensure no loss, that is, the price cost > =0.
The formula is 200 z-120 > =0,
Then z & gt=0.6,
That is, the maximum discount is 60%.
Is that clear? You can contact me again if you don't understand!
Test and analysis: From the nature of N(x), we can know that when x is odd, the largest odd factor of x is obviously itself. So N(x)=x, so we can decompose and calculate the s