Given a=4, b=0.3, c=2, what is the value of the formula 2a-6b+3c.
已知a=4，b=0.3，c=2，式子2a-6b+3c的值是多少．
<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<gadget id="calculator">6 * 0.3</gadget>
<output>1.8</output>

<gadget id="calculator">8 - 1.8</gadget>
<output>6.2</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">6.2 + 6</gadget>
<output>12.2</output>

<result>12.2</result>