Question

What is the slope and y intercept of `y=3.75`?

Answer 1

This function (linear) representes a constant which is fixed at the value of 3.75; graphically it representes a straight line passing through the point of coordinates `(0 ; 3.75)` on the y axis and parallel to the x axis.

Being a constant it never changes so that its slope (that representes how y changes for each change in x) is zero.

Considering the general form of a linear function:
`y=ax+b`
where the real number `a` representes the slope and the other real number `b` represent the intercept on the y axis, for your function we have:
`y=0x+3.75`