If the 3rd and the 9th term of an ap are 4 and -8 respectively, which of which term of this is zero

If the 3rd and the 9th term of an ap are 4 and -8 respectively, which

1.	If the 3rd and the 9th term of an ap are 4 and -8 respectively, which of which term of this is zero
Answer» a+2d=4. (1)a+8d=-8. (2)Subtract eq 1 and 2a+2d=4a+8d=-8(-)(-). (+)----------------6d=12 d= -2Replace in eq 1a + 2(-2)=4a-4=4a=4+4a=8an=a+(n-1)d 0= 8+(n-1)-2 0-8 =(n-1)-2-8/-2 =n-14=n-14+1 =n5=n--------- ನಂಗ್ ಗೊತ್ತಿಲ್ಲ??????