Because 8000-200 x >; =4400
So x < = 18.
So 1
X>= 19, when x is a positive integer, y 1= 18*4400+8000x.
Duiyi
y2=0.75*8000x=6000x
When x(8000-200x) =6000x, x= 10.
So x < 10, y1> Y2, choose B.
X= 10, y 1=y2, choose one.
x & gt 10,y 1 & lt; Y2, choose a family.
I hope I can help you, wish you progress in your study, and don't forget to adopt it!