Question

The first term of an arithmetic sequence is -5, and the tenth term is 13. Find the common difference.?

Answer 1

okay so what you can do is this:
\[U _{1}=-5\]
the tenth term is
\[U _{10}= 13\]

just do
\[U _{n}=u _{1}(n-1)d\]
plug in
-5 for u1
because u1 is the first term.

so plug in the other term which is U10 =13
10=n because it is the term we are using because we are making it equal to 13 to find the d!
13 = -5 (10-1)d
13= -45d
divide 13/-45 to get d alone
you get -13/45
or -0.2888...

is that understandable? ;p

Answer 2

yeah thanks