Jackson had $25 to spend on groceries . after purchasing 5 cantaloupes he had $2.50 left how much did each cantaloupe cost

Since the price of the cantaloupes is unknown, it will have to represented by a variable. Let's use x.
If Jackson starts with $25 and buys 5 cantaloupes of an unknown price, this subtracts 5 times the amount of 1 cantaloupe (which is x) from that $25.
This is shown as 25 - 5x.
After spending that money, he has $2.50 left over.
This means 25 - 5x = 2.50.
Now you just need to solve this by first isolating the variable.
First, subtract 25 from both sides.
25 - 5x - 25 = -5x
2.50 - 25 = -22.5
Then, divide both sides by -5. It's -5 since 5 is the coefficient and it's negative, so -5.
-5x / -5 = x
-22.5 / -5 = 4.5
This means x = 4.5.
And if x is 4.5, then that means the cost of 1 cantaloupe is $4.50.