Question

Write an algebraic expression of a flat rate of $25.00 and $.50 per mile

Answer 1

Think:  slope-intercept form of the equation of a straight line:  y=mx+b.
Here the "flat rate" of $25 is "b" and the "slope" of the line is $0.50/mile.

Thus, the correct algebraic expression is 

y=($0.50/mile) + $25.

Answer 2

0.50x+25 would be the expression form of the situation