Question

The eighth term of a linear sequence is 26. The term-to-term rule is 'add 3

Work out the fourth term of the sequence.
Explain the method you used to solve this problem.

Answer 1

• Common difference=d=3

Let a be first term

`\\ \rm\longmapsto a_8=a+7d`

`\\ \rm\longmapsto 26=a+7(3)`

`\\ \rm\longmapsto a=26-21`

`\\ \rm\longmapsto a=5`

Now

`\\ \rm\longmapsto a_4=a+3d`

`\\ \rm\longmapsto a_4=5+3(3)`

`\\ \rm\longmapsto a_4=5+9`

`\\ \rm\longmapsto a_4=14`