How do you write the nth term rule for the arithmetic sequence with #a_7=34# and #a_18=122#?
Subtracting firt equation from second equation, we get
The given data are
We can set up 2 equations
By method of elimination using subtraction, let us use first and second equations
By subtraction, we have the result
Solving now for
We can write the
God bless....I hope the explanation is useful.