51 ÷ r = (- 51). Find 'r'
r = 2
r = 1
r = -1
r = 3
51 ÷ (-1) = (-51) [∵51−51=(−1)]
Which of the following best describes the terms of the series? 12nC1 - 23nC2 + 34nC3...................(−1)n+1 1n+1nCn