If x=2 is the solution of equation 9-x=a-3, what is a?
若x=2是方程9-x=a-3的解，则a是多少？
<gadget id="calculator">9 - 2</gadget>
<output>7</output>

<gadget id="calculator">7 + 3</gadget>
<output>10</output>

<result>10</result>