Solve the equation: 3x+(30-x)*2=830.
解方程：3x+(30-x)*2=830．
<gadget id="calculator">30 * 2</gadget>
<output>60</output>

<gadget id="calculator">830 - 60</gadget>
<output>770</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<gadget id="calculator">770 / 1</gadget>
<output>770</output>

<result>770</result>