热心网友
题中应为a+2b＝3吧将a=3-2b代入ab=1得(3-2b)*b=12b^2-3b+1=0b=1 or b=0.5a=1 or a=2a-2b=-1 or 1
热心网友
a +2b=3,得a=3-2b代入ab=1,得2b^2-3b+1=0,b=1,b=1/2,所以a=1,a=2求a-2b的值为-1或1
题中应为a+2b＝3吧将a=3-2b代入ab=1得(3-2b)*b=12b^2-3b+1=0b=1 or b=0.5a=1 or a=2a-2b=-1 or 1
a +2b=3,得a=3-2b代入ab=1,得2b^2-3b+1=0,b=1,b=1/2,所以a=1,a=2求a-2b的值为-1或1