Question 1083646

given:
{{{a[4]=27}}}
{{{a[1]+a[4]=42}}}

{{{a[1]=42-a[4]}}}

{{{a[1]=42-27}}}

{{{a[1]=15}}}

find common difference using formula below:

{{{a[n] = a[1] + d(n-1)}}}

{{{a[4] = a[1] + d(4-1)}}}

{{{27= 15+ d(3)}}}

{{{27-15=3d}}}

{{{3d=12}}}

{{{d=4}}}

so, terms are:

{{{a[1]=15}}}

{{{a[2]=15+4=19}}}

{{{a[3]=19+4=23}}}-> your answer

{{{a[4]=23+4=27}}}