If the width of a rectangle increases by 2cm, the area increases by 10cm**2. At this time, it happens to be a square. What is the area of the original rectangle in cm**2?
一个长方形的宽增加2cm，则面积增加10cm**2，这时恰好是一个正方形，原来的长方形面积是多少cm**2．
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<result>15</result>