Question 1018520

You've overconstrained the system.
You have three equations but only two unknowns.
Here's the solution only using {{{a[2]}}} and {{{a[8]}}}
Check the problem setup and repost.
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{{{a[2]=a[1]+(2-1)*d=4/15}}}
1.{{{a[1]+d=4/15}}}
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{{{a[8]=a[1]+(8-1)*d=-24/15}}}
2.{{{a[1]+7d=-24/15}}}
Subtract eq. 1 from eq. 2,
{{{a[1]+7d-a[1]-d=-24/15-4/15}}}
{{{6d=-28/15}}}
{{{d=-14/45}}}
Then use either equation to solve for {{{a[1]}}}.
{{{a[1]+(-14/45)=4/15}}}
{{{a[1]=12/45+14/45}}}
{{{a[1]=26/45}}}