Question 1192990
<pre>

     <u>        x^2 + 0x - a</u>
x + 2)x^3 + 2x^2 - ax - 8
      <u>x^3 + 2x^2</u>
            0x^2 - ax 
            <u>0x^2 + 0x</u>
                  -ax - 8 
                  <u>-ax -2a</u>
                     -8+2a

The remainder should equal 0, so 

                     -8+2a = 0
                        2a = 8
                         a = 4
                         

Edwin</pre>