When X=how much, the values of 4X-8 and 5X-12 are equal.
当X=多少时，4X-8与5X-12的值相等．
<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<gadget id="calculator">4 / 1</gadget>
<output>4</output>

<result>4</result>