# C++ > Mathematics Code Examples

## Program to solve a 3 Variable Linear Equation

``` Program to solve a 3 Variable Linear Equation #include<stdio.h> #include<conio.h> #include<stdlib.h> main() { clrscr(); float a,b,c,d,l,m,n,k,p,D,q,r,s,x,y,z; printf("PROGRAM TO SOLVE THREE VARIABLE LINEAR SIMULTANEOUS EQUATIONS "); printf("The equations are of the form: ax+by+cz+d=0 lx+my+nz+k=0 px+qy+rz+s=0 "); printf("Enter the coefficients in the order a,b,c,d,l,m,n,k,p,q,r,s "); scanf("%f%f%f%f%f%f%f%f%f%f%f%f",&a,&b,&c,&d,&l,&m,&n,&k,&p,&q,&r,&s); printf(" The equations you have input are: "); printf(" %.2f*x + %.2f*y + %.2f*z + %.2f = 0 ",a,b,c,d); printf(" %.2f*x + %.2f*y + %.2f*z + %.2f = 0 ",l,m,n,k); printf(" %.2f*x + %.2f*y + %.2f*z + %.2f = 0 ",p,q,r,s); D = (a*m*r+b*p*n+c*l*q)-(a*n*q+b*l*r+c*m*p); x = ((b*r*k+c*m*s+d*n*q)-(b*n*s+c*q*k+d*m*r))/D; y = ((a*n*s+c*p*k+d*l*r)-(a*r*k+c*l*s+d*n*p))/D; z = ((a*q*k+b*l*s+d*m*p)-(a*m*s+b*p*k+d*l*q))/D; printf("The solutions to the above three equations are : "); printf(" x = %5.2f y = %5.2f z = %5.2f ",x,y,z); getch(); return 0; } ```