Element A in the diagram absorbs 30 W of power. Calculate V_x.

#### Solution:

### In our question, element A **absorbsĀ **power which means current should be entering the positive terminal, however, we can see that in the diagram, current is in fact going in the opposite direction.

### We know that p=vi

### We need to find V_x so we will isolate for v.

### V_x=\frac{p}{i}

### Substituting our values gives us:

### V_x=\frac{30W}{-2A}

### V_x=-15v

###### This question can be found in Basic Engineering Circuit Analysis, 10th edition, chapter 1, question 1.23.