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x+y=5k, x-y=9k相加2x=14k,x=7k所以y=x-9k=-2k代入2x+3y=614k-6k=68k=6k=3/4x=3y,所以y=x/3代入y+4z=0x/3+4z=0x/3=-4z所以x/z=-4*3=-12x与y相等所以x=y代入4x+3y=1 4x+3x=17x=1x=1/7,y=x=1/7代入ax+(a-1)y=3a/7+(a-1)/7=3a+a-1=3*72a-1=21a=113(x-3)+10(2/3+y)=1322(x-3)+5(2/3+y)=27令a=x-3,b=2/3+y则3a+10b=13 (1)22a+5b=27 (2)(1)-2*(2)3a+10b-44a-10b=13-27*2-41a=-41a=1,代入(2)22+5b=27b=1所以x=a+3=4y=b-2/3=1/3 |
