It is known that x=5 is the solution of the equation ax-16=12+a, so what is a=?
已知x=5是方程ax-16=12+a的解，那么a=多少．
<gadget id="calculator">12 + 16</gadget>
<output>28</output>

<gadget id="calculator">28 / 4</gadget>
<output>7</output>

<result>7</result>