If f(x)=1-x, whixh value is equivalent to |f(i)|

Find the slope of the line y =8/9x + 1.

How to do this , and can some one explain

Samantha is growing a garden in her back yard. she spend $90 setting up the garden bed and buying the proper garden supplies. in addition, each seed she plants cost $0.25. a. write the function f(x) that represents samantha's total cost on her garden. b. explain what x represents. c. explain what f(x) represents. d. if samantha plants 55 seeds, how much did she spend in total?