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Beijing normal university printing plate eighth grade mathematics exercise book ii
1 、( 1)y 1 = 25+0.4x y2 = 0.6x

(2) When x < 125min, A is economical; When x= 125min, A and B are the same; When x= 125min, b is economical.

2、y 1=0.58x y2=0.28x+600

② When y 1=y2= 1500,

y 1= 1500=0.58x

x≈2586

y2= 1500=0.28x+600

x≈32 14

Choose road transportation

When x= 1500,

y 1=0.58× 1500=870

y2 = 0.28× 1500+600 = 1020

Choose railway transportation