解
a²+b²-4a-2b+5=0
(a²-4a+4)+(b²-2b+1)=0
(a-2)²+(b-1)²=0
∴a-2=0,b-1=0
∴a=2,b=1
∴(√a+b)/√3b-2√a
=(√2+1)/(√3-2√2)
=(√2+1)/(√(√2-1)²
=(√2+1)/(√2-1)
=(√2+1)²/(2-1)
=3+2√2
解
a²+b²-4a-2b+5=0
(a²-4a+4)+(b²-2b+1)=0
(a-2)²+(b-1)²=0
∴a-2=0,b-1=0
∴a=2,b=1
∴(√a+b)/√3b-2√a
=(√2+1)/(√3-2√2)
=(√2+1)/(√(√2-1)²
=(√2+1)/(√2-1)
=(√2+1)²/(2-1)
=3+2√2