Hello! This problem is almost same as last problem i posted but still i am stuck. Its problem nr 42 i need help with

My progress:

(x^2-4)/(x-2)=(x+2) so at when lim goes to x->2 negative we know it shall be 4 so now we use number two that is in range 2<x<3 what we know is that when x=2 the answer shall be 4 because if its continuous there need to be lim same on negative and possitive. So we got the equation a2^2-2b=1 now im pretty stuck and dont know what to do.