When x=how many, 7x-8 and 5x+2 are equal.
当x=多少时，7x-8与5x+2两式相等．
<gadget id="calculator">8 + 2</gadget>
<output>10</output>

<gadget id="calculator">7 - 5</gadget>
<output>2</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<result>5</result>