Question

What is the explicit rule for the sequence in simplified form?

−1,−4,−7,−10,−13…


an=4−5n

an=−4−3n

an=2−3n

an=−6−5n

Answer 1

an = a1 + (n - 1).r

r = a2 - a1

r = -4 - (-1)

r = -4 + 1

r = -3

an = a1 + (n - 1).(-3)

an = -1 + (n - 1).(-3)

an = -1 + (-3n + 3)

an = -1 - 3n + 3

an = 2 - 3n