## anonymous one year ago Write the explicit formula that represents the geometric sequence -2, 8, -32, 128

1. SolomonZelman

r=-4 (u mulitply times -4 each time). $$a_1$$=-2 (that is your first term). --------------------------------- The general formula for geometirc sequence is: $$a_n$$ = $$a_1$$ • $$\rm r$$$$^{(n-1)}$$ plug in the common ratio $$\rm r$$ and the first term $$a_1$$, and there is your answer.

2. anonymous

I'm sorry I'm still lost

3. SolomonZelman

what exactly do you have a problem with?

4. anonymous

so my answer is a=-2*-4 (n-1)

5. anonymous