So x 1+x2=-2a/a? -3

x 1x2=2/a？ -3

AB slope k = (y2-y1)/(x2-x1) = (ax2+1-ax1) = a.

If AB is symmetric about y=x+2, the slope is-1/2.

a=- 1/2

Carry evaluation x 1=(-2+2 root number 23)/1,Y 1 = (12 root number 23)/ 1 1.

X2=(-2-2 root number 23)/ 1 1, Y2 =( 12+ root number 23)/1.

The distances are (root number115+16)/1,(root number115-16)//respectively.

The distances are not equal, so a=- 1/2 does not hold.

So there is no a.