Ask your own question, for FREE!
Algebra 23 Online
OpenStudy (lanadelbey):

What are the next three terms of the following sequence? -10, 20, -40, 80

OpenStudy (lanadelbey):

@mathstudent55 @akgorgeous

jimthompson5910 (jim_thompson5910):

Do you see any pattern with this set of numbers?

OpenStudy (lanadelbey):

yes, every other number is negative. Also, the first two numbers are 30 apart and the second two are 120 apart

OpenStudy (lanadelbey):

@jim_thompson5910

jimthompson5910 (jim_thompson5910):

if we had 10, 20, 40, 80, then what do you notice? Hint: multiplication by some fixed number happens each time

OpenStudy (lanadelbey):

each one is multiplied by 2 oh my gosh thank you

jimthompson5910 (jim_thompson5910):

yep so the pattern is to multiply each term by -2 to get the next term

OpenStudy (lanadelbey):

-160, 320, -640, 1280

OpenStudy (lanadelbey):

is that right?

jimthompson5910 (jim_thompson5910):

you only need 3 terms, but you have the right idea. Nice job

OpenStudy (aasthasalo):

ans is -160

OpenStudy (sarahmc):

each time it multiplies by -2 so 80 * -2 = -160... and so on. Hope I helped :) x

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!