Y=1/1+3 (been a while)
Y=mx+b
Your y intercept represents b, what is your y intercept? It’s where the line cross the y axis.
The m in your equation is the slope, your slope is 1 over 1 or simply put 1.
Another way to write this equation is:
Y=1x+3
I like to write it the first way because visually you understand your numerator is 1 (your rise) and your denominator is 1 (your run or vertical movement)