if 4th term of an arithmetic progression is 3 times the 1st term nd 7th term exceeds twice the third term by 1. find the first term and common difference

Answer 1

T4 = 3T1
T7 = 2T3 + 1

Now just plug in the values for Tn and you have

a+3d = 3a
a+6d = 2(a+2d)+1

Now just solve for a and d.

Answer 2

a=5 and d=4

Answer 3

but the answer is not clear, how the first and common difference is solve