Question

Which relation is a function?
A. http://static.k12.com/calms_media/media/1417000_1417500/1417250/1/5777f7f0552e79387010b19944ad5ad6382e1309/MS_PA_130905_170056.jpg
B. http://static.k12.com/calms_media/media/1417000_1417500/1417251/1/6b2bdac1e2fa3c7b9c55470a43d119d61df2b5e9/MS_PA_130905_170057.jpg
C. http://static.k12.com/calms_media/media/1417000_1417500/1417252/1/89867371590aef555fd347857ff82efabb475a92/MS_PA_130905_170058.jpg
D. http://static.k12.com/calms_media/media/1417000_1417500/1417253/1/b34d9ef463e10ac51765581222931bb6f3b55e01/MS_PA_130905_170059.jpg

Answer 1

@jim_thompson5910

Answer 2

#1

Answer 3

All the others have somewhere where an x-value has two corresponding y-values. An easy way to verify if you have a function is to imagine a vertical line sweeping your graph from left to right. If the vertical line touches two points (for a given x-value) at any time, then you don't have a function.