急求解啊!一定要标准的啊!!!
{1995=8.6*8.6a+8.6b+c
{2000=10.4*10.4a+10.4b+c
{2005=12.9*12.9a+12.9b+c
学过二元一次方程组的兄弟帮忙解下啊!!!
参考答案:1995=8.6*8.6a+8.6b+c
{2000=10.4*10.4a+10.4b+c
{2005=12.9*12.9a+12.9b+c
化简:
73.96a+8.6b+c=1995....(1)
108.16a+10.4b+c=2000....(2)
166.41a+12.9b+c=2005.....(3)
(2)-(1):
34.2a+1.8b=5......(4)
(3)-(2):
58.25a+2.5b=5........(5)
(4)*2.5-(5)*1.8
-19.35a=3.5
a=-70/387=-0.18
代入(5):
58.25*(-70/387)+2.5b=5
b=2405/387=6.21
代入到(1):
73.96*(-70/387)+8.6*2405/387+c=1995
c=29324/15=1954.93
所以:
a=-70/387=-0.18
b=2405/387=6.21
c=29324/15=1954.93
做得好辛苦啊!