After a pair of opposite sides of a square are increased by 7 meters, the area is increased by 42 square meters. What is the area of the original square?
一个正方形的一组对边分别增加7米后，面积增加42平方米，原来正方形的面积是多少？
<gadget id="calculator">42 / 7</gadget>
<output>6</output>

<gadget id="calculator">6 * 6</gadget>
<output>36</output>

<result>36</result>