If change in internal energy -80 J. The work done by system is +40 J. Calculate the heat change.

Explanation

To solve the problem step by step, we will use the first law of thermodynamics, which relates the change in internal energy (ΔU), heat (Q), and work (W) done by the system.

### Step-by-Step Solution:

1. **Identify the given values:**
- Change in internal energy (ΔU) = -80 J
- Work done by the system (W) = +40 J

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