Given equations are
x+(a2−3a+3)y=a2 and
x+y=1To have unique equations, a1a2≠b1b2
where, a1 and a2 are X-coefficients
b1 and b2 are Y-coefficients of the given equations.
Therefore,11≠a2−3a+3
a2−3a+2≠0
a≠2 or a≠1
The values of a∈R−{1,2} for the unique solutions.