4a2+b2-4a-6b+10=0
4a²-4a+1+b²-6b+9=0
(2a-1)²+(b-3)²=0
∴2a-1=0
b-3=0
∴a=1/2
b=3

(2/3a√9a+b2√a/b3)-(a2√1/a-5a√b/a)
=2√a+√ab-√a+5√ab
=√a+6√ab
=√(1/2)+6√(3/2)
=√2/2+3√6a²√1/a=√2？不是等于2√2么？我看错你的a了(2/3a√9a+b2√a/b3)-(a2√1/a-5a√b/a)=2a√a+√ab-a√a+5√ab=a√a+6√ab=1/2×√(1/2)+6√(3/2)=√2/4+3√6a²√1/a=√2/4