If 5x-3y+5=10.8, then, 10x-6y-5=how much.
若5x-3y+5=10.8，那么，10x-6y-5=多少．
<gadget id="calculator">10.8 * 2</gadget>
<output>21.6</output>

<gadget id="calculator">21.6 - 15</gadget>
<output>6.6</output>

<result>6.6</result>