Define x☆y=3x-2y, known x☆(4-1)=7, find the value of x.
定义x☆y=3x-2y，己知x☆(4-1)=7，求x的值．
<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<gadget id="calculator">7 - 2</gadget>
<output>5</output>

<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">13 / 3</gadget>
<output>13/3 = around 4.333333</output>

<result>13/3 = around 4.333333</result>