Solve the equation: 7x-9=5x.
解方程：7x-9=5x．
<gadget id="calculator">7 - 5</gadget>
<output>2</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<result>9/2 = around 4.5</result>