26. Find the sum of all possible values of $a$ such that the following equation has real root in $x$ :
$$
(x-a)^{2}+\left(x^{2}-3 x+2\right)^{2}=0 .
$$
26 Ans: 3 .
$$
x^{2}-3 x+2=x-a=0 \Longrightarrow a=1 \text { or } a=2 \text {. }
$$