令y=kx z=1-x-y M=xy+2yz+3xz =x·kx+2kx(1-x-kx)+3x(1-x-kx) =kx²+2kx-2kx²-2k²x²+3x-3x²-3kx² =-(2k²+4k+3)x²+(2k+3)x =-(2k²+4k+3)[x- (2k+3)/(4k²+8k+6)]²+ 1/(8k²+16k+12) 1/(..
