.75x + 8 = y (x being the number of lines) (8 being the initial charge) Then substitute x with any of the numbers above (multiply 0.75 with any) then add 8 dollars in the end..
I won’t! it’s very pretty!
90-x*30=80
90-30x=80
90-90-30x=80-90
-30x=-10
Divide by -30 for -30x and -10
-30/-30x=-10/-30
x=1/3
