解:x²+y²-8x-6y+25=〔x-4〕²+〔y-3〕²=0
〔x-4〕²≥0,〔y-3〕²≥0
所以x=4,y=3
3x+4y的值是24
x²+y²-8x-6y+25=0
==>x²-8x+16+y²-6y+9=0
==>(x-4)²+(y-3)²=0
==>x=4 y=3
x²+y²-8x-6y+25=0
(x-4)²+(y-3)²=0
∴x-4=0,y-3=0
x=4,y=3
∴3x+4y=3×4+4×3=24
x²+y²-8x-6y+25=0
(x-4)²+(y-3)²=0
∴x-4=0且y-3=0
∴x=4,y=3
∴3x+4y=24
(x-4)2+(y-3)2=0
x=4 y=3
3x+4y=24