When a=5, the equation 2x+3a=30, then x=how much.
当a=5时，方程2x+3a=30，则x=多少．
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">30 - 15</gadget>
<output>15</output>

<gadget id="calculator">15 / 2</gadget>
<output>15/2 = around 7.5</output>

<result>15/2 = around 7.5</result>