Question

If x= 0, 1, 2, and 3 and y=1, 1.5, 2, and 2.5, then what is the "y=" function?

Answer 1

The values are increasing equally so it's a linear function.
The formula is $y=mx+b$
For $x=0$, $y=1$ so $b=1$ (y-intercept).
Take some point and put its coordinates into the equation to find $m$ (slope).
$2=m\cdot2+1\\ 2m=1\\ m=\dfrac{1}{2}\\\\ \boxed{y=\dfrac{1}{2}x+1}$