Question

用C语言解二元一次方程要用什么公式吗??

Answer 1

二元一次方程一般为

ax+by+c=0

dx+ey+f=0

输入a,b,c,d,e,f这些系数后，

转化为x=(-by-c)/a,代入,d*(-by-c)/a+ey+f=0

化简-b*d*y/a-c*d/a+ey+f=0

(ea-b*d)*y/a=c*d/a-f

y=a*(c*d/a-f)/(ea-b*d)

解出y后，x=(-by-c)/a

代码实现：

#include
<stdio.h>
void
main()
{
double
a,b,c,d,e,f,x,y;
scanf("%lf
%lf
%lf
%lf
%lf
%lf",&a,&b,&c,&d,&e,&f);
y
=
a*(c*d/a-f)/(e*a-b*d);
x
=
(-b*y-c)/a;
printf("%lf\n%lf\n",x,y);
}