Here’s a graph from desmos!
So firstly, multiply both sides by t: 
Next, add both sides by v0, and your answer will be: 
Answer:
g=3
Step-by-step explanation:
f(g)=g²+3g
Personally, I would do a guess and check to figure this out.
Let's try a number like 3. Insert it -
f(3)=3²+3(3) =9+9=18
Therefore, the answer is 3.
So we are given two points, say P1(4,7), P2(x,19).
Slope is given by
m=3=(y2-y1)/(x2-x1)=(19-7)/(x-4)
solve for x
3=(19-7)/(x-4)
cross multiply
3(x-4)=12
3x-12=12
3x=12+12=24
x=8