Question

Find the 77th term of the arithmetic sequence 8,26,44, …

Answer 1

Step 1: Write out the formula for the nth term of an arithmetic sequence

`U_n=a+(n-1)d`

Step 2: Find a and d and substitute them into the formula

`\begin{gathered} a=8 \\ d=U_2-U_1 \\ d=26-8=18 \\ Un=8+(n-1)18 \end{gathered}`

Step 3: find the 77th term

`\begin{gathered} U_(77)=8+(77-1)18 \\ =8+(76)18 \\ =8+1368 \\ U_(77)=1376 \end{gathered}`

Hence, the 77th term is 1376