When x=7, what is the value of the algebraic expression x**2-1.
当x=7时，代数式x**2-1的值是多少．
<gadget id="calculator">7 ** 2</gadget>
<output>49</output>

<gadget id="calculator">49 - 1</gadget>
<output>48</output>

<result>48</result>