You can
put this solution on YOUR website!You're on the right track. You have 2 of the three equations needed to solve this problem. Why are 3 equations needed? You have 3 variables, so you need 3 equations.
Since "The tens digit exceeds the hundreds digit by the same amount that the units digit exceeds the tens digit", this means that the third equation is

Start with the third equation

Add

to both sides.

Add

to both sides.

Subtract

from both sides.

Combine like terms.

Rearrange the equation.
-----------------------------------------

Move back to the first equation

Plug in

Combine like terms.

Divide both sides by

to isolate

.

Reduce. So the tens digit is 4
--------------------------------------

Go back to the previously isolated equation

Plug in

Multiply
-------------------------------------

Move onto the second equation

Plug in

and

Multiply

Distribute the negative.

Distribute.

Combine like terms on the left side.

Add

to both sides.

Combine like terms on the right side.

Divide both sides by

to isolate

.

Reduce. So the units (or ones) digit is 5
--------------------------------------------

Go back to the isolated equation

Plug in

Subtract. So the hundreds digit is 3
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Answer:
So the digits are

,

, and
This means that the original number is 345
Note: I appreciate you showing your work.