yup it was a linker problem

yea it was a linker problem I figured that out

I also found many other problems with my code so I fixed it

Code:

// calculate loan payments on a mortgage

#include <stdio.h>

#include <math.h>

int main()

{

// declare all variables

double principal_amount = 0;

float interest_rate = 0.0 ;

int years = 0;

system ("clear");

printf ( " This program will calculate your monthly payment of a Home Mortgage\n\n" );

printf ( " First it will need some info \n\n" );

printf ( " Please enter the loan amount: " );

scanf ( "%d", &principal_amount );

printf ( "\n\n Next how many years would you like the loan for? " );

scanf ( "%d", &years );

printf ( "\n\nAnd last what intrest rate are you getting? " );

scanf ( "%3f", &interest_rate );

int number_of_payments = years * 12;

float monthly_interest = interest_rate / 12;

double monthly_payment = principal_amount * pow ( 1.0 + monthly_interest, number_of_payments ) * monthly_interest / ( pow ( 1.0 + monthly_interest, number_of_payments ) - $

printf ( "\n\n Your monthly payment would be $%d dollars\n\n ", monthly_payment );

printf ( "\n Principal amount is %d", principal_amount );

printf ( "\n Number of payments is %d", number_of_payments );

printf ( "\n Monthly interest is %f", monthly_interest );

printf ( "\n Interest rate is %3f\n", interest_rate );

return 0;

}

it runs now :)