Question 1135688
<pre>
a<sub>1</sub> = 600
d = 3.1

{{{a[n]=a[1]+(n-1)d}}} <-- the formula for the nth term of an A.P.

{{{a[n]=600+(n-1)(3.1)}}} <-- substituted for a<sub>1</sub> and d

{{{a[n]=600+3.1(n-1)}}}  <-- moved the 3.1 to the left of (n-1)

{{{a[n]=600+3.1n-3.1)}}} <-- distributed

{{{a[n]=596.9+3.1n)}}} <-- combined like terms

Edwin</pre>