Suppose a△b=4a-3b, then, 8△7=how much.
设a△b=4a-3b，那么，8△7=多少．
<gadget id="calculator">4 * 8</gadget>
<output>32</output>

<gadget id="calculator">3 * 7</gadget>
<output>21</output>

<gadget id="calculator">32 - 21</gadget>
<output>11</output>

<result>11</result>