Find the explicit formula for the given sequence. -4, 12, -36, 108,...

a
a_n=-4·(-3)^{n-1}

b
a_n=4·3^{n-1}

c
a_n=15·3^{n-1}

d
a_n=5·3^{n-1}

Option a.) an = -4(-3)^(n-1)

2,600 divided by 80 = 32.5

step-by-step explanation:

38.5

step-by-step explanation:

lets say, first number = r

second number = 3r+7

total = 49

(r)+(3r+7)= 49

4r+7 = 49

4r = 42

r = 42/4

r= 10.5

3r+7 = 3(10.5)+7 = 38.5

hope this