When x=2, y=1, what is the value of the formula 2x+8y
当x=2，y=1时，式子2x+8y的值是多少
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">8 * 1</gadget>
<output>8</output>

<gadget id="calculator">4 + 8</gadget>
<output>12</output>

<result>12</result>