Which ratio is not equivalent to the other three? a.2/5 b.12/15 c.6/15 d.18/45

Lets do equal fractions by multiplying and dividing them by a number:
(2/5)(3/3) = 6/15
= (6/15)(3/3) = 18/45
so these are equivalent:
2/5 = 6/15 = 18/45

The fraction 12/15 is not equivalent to them, because there is no number that multiplying and dividing it gives the others.

Absolute value graph shifted point 5 up