解方程组:2008x+2009y=2007 2010x+2001y=2009
问题描述:
解方程组:2008x+2009y=2007 2010x+2001y=2009
答
2008x+2009y=2007 ①
2010x+2001y=2009 ②
②-①得
2x-8y=2
∴x=(2+8y)/2=1+4y ③
将③代入②中,得
2010(1+4y)+2001y=2009
2010+8040y+2001y=2009
10041y=-1
y=-1/10041
将y=-1/10041代入②中,即可求出x
x=[2009-2001×(-1/10041)]/2010搞错了是2010x+2011y=20092008x+2009y=2007①2010x+2011y=2009②②-①得2x+2y=2x+y=1x=1-y ③将③代入②中,得2010(1-y)+2011y=20092010-2010y+2011y=2009y=-1将y=-1代入②中,即可求出xx=[2009-2011×(-1)]/2010=(2009+2011)/2010=4020/2010=2∴原方程组的解为x=2,y=-1