Check the picture below.
the line you drew for y = 2x +3 is correct, now recall that the line for x = 3 is just a vertical line, in red, and that y = 2 is just a horizontal line, in green.
now all lines are solid because all are using ⩽ or ⩾, meaning the borderline is included, and you can do a "true" "false" region check if you wish, but less than 3 is to the left of the red one, greater than 2 is above the green one and less than 2x + 3 is just to its left.
Let's assume
It started in 2000
so, t=0 in 2000
we can use formula
we can plug value
In 2005, the same survey was made and the total amount of gamma ray bursts was 7.3 million
so, at t=2005-2000=5
P(t)=7.3 million
we can plug value and then we can solve for r
now, we can plug back
now, we have
P(t)=1 billion =1000 million
so, we can set it and then we can solve for t
approximately
Year is 2000+192
year is 2192................Answer