Arithmetic Sequence: Finding the First 3 Terms Using tn= t1+(n-1)d

[Vince604]

Homework Statement

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.

Homework Equations

The Attempt at a Solution

I'm trying to use the formula: tn= t1+(n-1)d but don't have right numbers. please show me step by step would be really helpful. Thanks

 

[ehild]

Homework Statement

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.

Homework Equations

The Attempt at a Solution

I'm trying to use the formula: tn= t1+(n-1)d but don't have right numbers. please show me step by step would be really helpful. Thanks

What is the 11th term of the sequence, in terms of t1 and d?
What are the 5th and 7th terms?

ehild

 

[symbolipoint]

This problem description has two unknown values which need to be solved. You can find a system of equations using information about the 11th term and the relationship between the 5th and 7th terms. Your unknown numbers to solve for first are d and t₁.

The relevant equation for part 2 of the homework template is t_n=t₁+(n-1)d

 

[Bonaparte]

I'll give you an even bigger hint than Symbol and ehild gave:
a(n) = a1 + (n-1)d
substitute 11...
53 = a1+10d
you can do the rest ;)

Thanks and good luck, Bonaparte

 

[Mark44]

Homework Statement

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.

Homework Equations

The Attempt at a Solution

I'm trying to use the formula: tn= t1+(n-1)d but don't have right numbers. please show me step by step would be really helpful. Thanks

From the PF rules:

On helping with questions: Any and all assistance given to homework assignments or textbook style exercises should be given only after the questioner has shown some effort in solving the problem. If no attempt is made then the questioner should be asked to provide one before any assistance is given. Under no circumstances should complete solutions be provided to a questioner, whether or not an attempt has been made.

In other words, we don't provide step-by-step solutions. We'll help you with the work you do.

 

[Vince604]

okay thanks