Which is a function?

A. (2,9),(-1,1),(-1,-2),(1,-1)

B. (2,9),(9,-1),(2,1)

C. (2,9),(9,2),(1,1)

D. {2,9,-1,1}

A. (2,9),(-1,1),(-1,-2),(1,-1)

B. (2,9),(9,-1),(2,1)

C. (2,9),(9,2),(1,1)

D. {2,9,-1,1}

A. (2,9),(-1,1),(-1,-2),(1,-1)

B. (2,9),(9,-1),(2,1)

C. (2,9),(9,2),(1,1)

D. {2,9,-1,1}

Tutors, please sign in to answer this question.

Burlington, NC

TO BE A FUNCTION: No vertical *(up and down)* line can cross more than one point of your graphed line. This means that your X coordinates
*(the first number in each pair)* cannot show up more than once in your set of ordered pairs.

Option C has the unique X coordinates of 2, 9, and 1. When graphed, your ordered pairs create an upside down V. Because there is no vertical line you could possibly draw that would intersect your graph in more than one place, you've got yourself a function.

Check out this website for some quick practice with visual aids: http://math.uww.edu/~mcfarlat/141/fn_test.htm

Jason L.

Top scoring professional SAT and ACT tutor; Practicing Attorney

Livingston, NJ

5.0
(8 ratings)

Sean B.

Talented Math and SAT tutor for all

New York, NY

5.0
(18 ratings)

Yang X.

Penn Triple Major - Finance / Excel / Chinese / Writing

Forest Hills, NY

5.0
(18 ratings)

- Math Help 3963
- Algebra 3736
- Calculus 1704
- Math Word Problem 2795
- Algebra 2 2685
- Word Problem 3735
- Algebra 1 3023
- Math Equations 841
- Math Help For College 1156
- Math Problem 718

Find a tutor fast. Get the app.

Are you a tutor? Get the app for tutors

© 2005 - 2016 WyzAnt, Inc. - All Rights Reserved

## Comments