To solve an inequality, you solve it just like an equation with an = sign
y-3 ≥ -12
Add 3 to both sides
y ≥ -9
What this means is that y could be any number as long as it’s greater than (bigger) or equal to -9, so y could equal -9, -3, 100, or 0 but could not equal -10,-11, -9.3, or anything less than -9
To graph this, first write in numbers below each of the lines. You want to show -9, a few numbers less than -9 and a few numbers greater than -9. It could look like this:
-11 -10 -9 -8 -7 -6 -5
Then, draw a filled in circle above -9. This shows that y can equal -9. Starting from where you drew the circle, draw an arrow to the right until the graph ends. This shows that y could be any of these numbers greater than -9, too.
I attached an example of a filled in number line for a different problem so you could see what it looks like. I hope this helps!