38*(x+0.5)+42x=259, x=how much.
38*(x+0.5)+42x=259，x=多少．
<gadget id="calculator">38 * 0.5</gadget>
<output>19</output>

<gadget id="calculator">259 - 19</gadget>
<output>240</output>

<gadget id="calculator">38 + 42</gadget>
<output>80</output>

<gadget id="calculator">240 / 80</gadget>
<output>3</output>

<result>3</result>