There is a rectangle, if its width is reduced by 3 decimeters, its area will be reduced by 45 square decimeters; if its length is reduced by 3 decimeters, its area will be reduced by 36 square decimeters. Find the area of the original rectangle?
有一个长方形，如果它的宽减少3分米，面积就减少45平方分米；如果长减少3分米，面积就减少36平方分米．求原来这个长方形的面积？
<gadget id="calculator">45 / 3</gadget>
<output>15</output>

<gadget id="calculator">36 / 3</gadget>
<output>12</output>

<gadget id="calculator">15 * 12</gadget>
<output>180</output>

<result>180</result>