Thread: Arithmetic Sequence

In an arithmetic sequence, the 11th term is 53 and the sum ofof the 5th and 7th terms is 56. Find the first 3 terms of the sequence.


I'm trying to use the formula: tn= t1+(n-1)d but cant figure out where to get the numbers. Please step by step on how to get answer would be really helpful. Thanks

Using the given information, we obtain two equations in two unknowns:





If we subtract the first equation from the second, we will eliminate and we can solve for . Then we can use this value to find from either of the original equations.

is t1 = 3?

Yes, so what is d?

oh sweet thanks so much! d=5 i got it now. everything fell into place

Yes, good work!