Your gunna need to need to add details m8.
Answer:
(x) = 
Step-by-step explanation:
let y = f(x) and rearrange making x the subject, that is
y = 5x + 4 ( subtract 4 from both sides )
y - 4 = 5x ( divide both sides by 5 )
= x
change x to
(x) and y back to x, thus
(x) = 
$65 if you include the $20 he already had in his account
Answer:
A.
Step-by-step explanation:
33.75 / 15 = 2.25 for one lunch