When a=3, b=1.5, c=2, what is the value of ab+2c
当a=3，b=1.5，c=2时，ab+2c的值是多少
<gadget id="calculator">3 * 1.5</gadget>
<output>4.5</output>

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

<gadget id="calculator">4.5 + 4</gadget>
<output>8.5</output>

<result>8.5</result>