Answer
Find out the equation which show how much money Mitch saved.
To proof
let us assume that the total money Mitch saved be x.
As given
Mitch earned $80, but spent $25 on a video game before adding the rest to the $285 he already saved.
than the equation becomes
x = 285 + (80 - 25)
x = 285 + 55
x = $ 340
Therefore the amount of money Mitch money be $ 340 .
Hence proved