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!