It is known that a=2.3, b=5; then what is the value of 8a-b+2a.
已知a=2.3，b=5；则8a-b+2a的值是多少．
<gadget id="calculator">8 * 2.3</gadget>
<output>18.4</output>

<gadget id="calculator">18.4 - 5</gadget>
<output>13.4</output>

<gadget id="calculator">2 * 2.3</gadget>
<output>4.6</output>

<gadget id="calculator">13.4 + 4.6</gadget>
<output>18</output>

<result>18</result>