find the equation to the tabole

I think it’s 1x+30
Alright...
x-1,2,4,5
Focus on 1,2 bc 1+1 =2
Now the y coordinates
y=20, x=1
Then y=10 and x=2
For the x rate the rise would be it’s increased by 1
and for the y rate the run would be it’s DECREASED by 10
-10/1
now we have to go backwards
So we add y=20 for x=1
20+10 =30
So, when x is 0 the y coordinate is 30