(x-2y+32)
โง 3ใคใฎๅฎๆฐx,y,zใฏ,x-2y+3z=5,x+yz=4ใๆบใใใจใใใใใฎใจใ,
x2+4y2+9z2ใฎๅคใๆฑใใใ
xยฒ + 4yยฒ + 9โยฒ
=xยฒ-2xy+3x2-2xy+4g-6yz+3x63292
=x2+4g2922-4xy-12gz+6zx
=25-4
(x-2y+32)-(4x+1282-6zz)
=21
2
= 5ยฒ - ( 42* +92 - (222)
2
4xy
+yz.
6
12
=25-(+y2-2x^ยฒ)