Please help fast i have no clue what this is meaning
ILL MARK U BRAINLIEST

A function is a relation that is either

one-to-one, meaning each output only has one inputmany-to-one meaning some outputs can have more that one input, but all inputs only have one output

So, That pic is cramped, don't even know what functions are being referenced but

from the a, b, c, d relation

It is not a function because some inputs have more that one output, which fails our man-to-one rule

From the equations

-3x = 15 is not a function, because it only has one input but more than one output breaking rule 12y=10 is a function because every input x has only one output y, it is many-to-one3x-0.25y=3 is a function, it is one to one

From the graph

the line is a function, since it is many-to-one

From the points

the x coordinate is the input, not points (2,6) and (2,3) have the same input for two outputs, breaking rule 2, that each input should have only one output. So the points are not a function

The last one bc that's a calendar

the answer would be c ≈ 18.852*3.14= 6.286.28*3=18.85