If it is stipulated that A△B=A*B-3A+4B, then 5△7=how much.
若规定A△B=A*B-3A+4B，那么5△7=多少．
<gadget id="calculator">5 * 7</gadget>
<output>35</output>

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

<gadget id="calculator">35 - 15</gadget>
<output>20</output>

<gadget id="calculator">7 * 4</gadget>
<output>28</output>

<gadget id="calculator">20 + 28</gadget>
<output>48</output>

<result>48</result>