After a cuboid is attached to a cube, the surface area increases by 28cm**2 compared to the original one. What is the surface area of the cube in cm**2?
一个长方体接上一个正方体后，表面积比原来增加了28cm**2，这个正方体的表面积是多少cm**2．
<gadget id="calculator">28 / 4</gadget>
<output>7</output>

<gadget id="calculator">7 * 6</gadget>
<output>42</output>

<result>42</result>