ABC taxi company charges 5x +4.50 this where 5x is the slope so per mile and b=4.50 it will charge $5 , so if it is 1 mile the total charge would be $9.50 as the mile goes on so does the m increases.
Acme charges $4x per mile + 1.50 where m=4 b=1.50 so for 1 mile it is $5.50
ABC charges $4 .00 over Acme