Question

Which sequence begins with 1 and follows this rule? multiply by 2 and add 1.

Answer 1

Change the information into an equation and do sequence. pull out any necessary information.
y = 2x + 1
starts at 1... so your first sequence is 1.
plug in x=1 then it becomes 3. then the next sequence you plug in 3 (, the answer to your previous solve) you get 7. continue to do this. next sequence you plug in x=7 into the equation y = 2x + 1.
thus, y = 2(7) + 1 =15... so forth...
therefore the answer is B.

Hope this helps :)