I have a problem that says "Find the rule of $a_1 = 11$ and $a_5 = 27$"
How would I find the rule, I have tried putting the answer into $a_n = a_1 + (n-1) d$, and I have also attempted to put both $a_1$ and $a_5$ into their own version on that formula.
Can someone put how to solve the equation in simple terms? My teacher went really fast while explaining this.
This requires a little working out. There is some hidden number $d$ for which $a_2 = a_1 + d$, $a_3 = a_2 + d$, $a_4 = a_3 +d$ etc. To get from $a_1$ to $a_5$ you will have to add $d$ four times, so $a_5 = a_1 + 4d$. Can you work things out from here?