When a=3, b=2, what is the value of formula 3a-2b?
当a=3，b=2时，式子3a-2b的值是多少．
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">9 - 4</gadget>
<output>5</output>

<result>5</result>