Find the first 3 terms:

a_1 = 1

a_n=-2a_{n-1}

Is the sequence in [1] geometric or arithmetic?

Write the explicit formula for

a_1 = 1

a_n=-2a_{n-1}

Write the explicit formula for

a_1 =7

a_n=5a_{n-1}

Write the explicit formula for

a_1 =8

a_n=a_{n-1}-2

Write the explicit formula for

a_1 =80

a_n=-\frac{1}{4}a_{n-1}