Answer:
4r ^2 +9r + 12
Step-by-step explanation:
Hope this helps! :)
Answer:
I'm not able to do it but I can tell you how
Step-by-step explanation:
make the 10a-9 equal 14a-25 solve for that a then use the answer to a to then plug in thst number in all of them and that would be your answer
Answer:

Step-by-step explanation:
Set up the equation:
Since C(t) gives the number of cars purchased in the t-th year after 1998, then make the number of cars equal to 15 000 and solve for t - the year:
20t^2 = 15000
t^2 = 750
t = 
The year will be simply 1998 + 5 \sqrt{30}