Question

plaz friend my questions solve it plz plz important question work write down copy plz​

Answer 1

here is your answer

hope it helps you

Answer 2

Answer:

so the sequence is:1,3,6,10,15,21,28,36,45...

Step-by-step explanation:

so, eighth and ninth triangular numbers are:38 and 46 now the task is pretty simple. by adding these two get 36 +45 = 81 which is a perfect square of 9