Getting the following error: expected '(' after 'if' [closed]

I am just beginning with cs50 and was trying out pset1 and was slowly modifying my code with conditions and checking it at every step so that errors don't pile up.

I wrote an if - else statement and some error is popping up however even after lot of inspection I am unable to comprehend it

    #include <stdio.h>
    #include <cs50.h>
    #include <math.h>

int main (void)
{
    long credit_number;
do
{
    credit_number = get_long("Number: ");
}
while (credit_number < 0);

if ((credit_number >= 340000000000000 && credit_number < 35000000000000) || (credit_number >= 370000000000000 && credit_number < 38000000000000))
{
    if
    {
        for (i=1; i < 8; i=i+2)
        {
           (2(credit_number % pow (10, i+1) - credit_number % pow (10, i))/pow (10 , i) + (credit_number % pow (10, i) - credit_number % pow (10, i-1))/pow (10 , i)) % 10 = 0
           printf("AMEX");
        }
    
    else
    {
        printf("INVALID");
    }
    }
}
else
{
    printf("INVALID");
}
    
}

The error I am getting is -

credit.c:17:5: error: expected '(' after 'if'
    {
    ^
1 error generated.
<builtin>: recipe for target 'credit' failed
make: *** [credit] Error 1

Kindly help me find the error I am making