1y =( 15+3)×x+(20+4)(2000-x)

(cost per tree × number of trees+cost per tree × number of trees)

= 18x+48000-24x

=-6x+48000

(0 & ltx & lt200)

2 From the meaning of the question:

0.95x+0.99×(2000-x)= 1960

-0.04x= 1960- 1980

x=500

So y =-6× 500+48000.

=45000

A: The total cost is 45,000 yuan.