1 , 3 , 6 , 10 , 15 1) What is the nth term of the sequence?

2) Use the nth term to work out the 21st term of the sequence.

First difference,

Second difference,

Third difference,

And so on.

Assuming the pattern holds on, we see that

i-th difference,

Then, nth term is,

Now, the 21st term in the sequence is,

answer: yes youre right.

step-by-step explanation:

step-by-step explanation:

divide, then simplify your answer.

1. make -15.66 ÷   5.8 a fraction. then divide.

2. simplify.  

3. final answer.