How many sides do 2 octagons, 4 pentagons, and 5 triangles have in all?

51

Step-by-step explanation:

2 octagons have 16 sides because an octagon has eight sides. So, 8x2=16.

4 pentagons have 20 sides because a pentagon has 5 sides. So,        4x5=20.

5 triangles have 15 sides because a triangle has 3 sides. So, 5x3=15.

In all, 16+20+15= 51

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value