What is the common ratio of the sequence? -2, 6, -18, 54,...

a. −3
b. −2
c. 3
d. 8

Ineed me i stuck and i don’t want to get it wrong

Girardo is using the model below to solve the equation . girardo uses the following steps: step 1 add 4 negative x-tiles to both sides step 2 add 1 negative unit tile to both sides step 3 the solution is which step could be adjusted so that gerardo's final step results in a positive x-value? in step 1, he should have added 4 positive x-tiles to both sides. in step 1, he should have added 3 negative x-tiles to both sides. in step 2, he should have added 4 negative unit tiles to both sides. in step 2, he should have added 1 positive unit tile to both sides.

What are the domain and range of the function f(x)=2^x+1