$\"\"$

The initial cost of the machine is $\"\"$ .

The machine cost depreciates at a rate of $\"\"$ per year.

The machine worth is $\"\"$ as much as before.

The cost of the machine after 1 year is $\"\"$ .

The machine cost after $\"\"$ years is $\"\"$ .

The cost of the machine after $\"\"$ years is $\"\"$ .

Find the cost of the machine after $\"\"$ years.

Substitute $\"\"$ in $\"\"$ .

$\"\"$

$\"\"$ .

Therefore, the cost of the machine after $\"\"$ years is $\"\"$ .

$\"\"$

The cost of the machine after $\"\"$ years is $\"\"$ .