Answer : The equation could you use to find p is, 
Step-by-step explanation :
Let the cost of 1 pen be, 'x'
and the cost of 1 pencil is, 'p'
As we are given that total cost of 1 pen and 1 pencil is $2.10. The equation will be:
............(1)
And we have also given that the pen costs twice as much as a pencil. The equation will be:
............(2)
Now put the equation 2 in equation 1, we get:


Thus, the equation could you use to find p is, 
The money in the Felix's account will be $6798 when he is 21.
<u>Step-by-step explanation:</u>
It is given that,
- The amount deposited is $2000.
- The account earns 6% compound interest.
- It is compounded annually for 21 years.
<u>To find the money in Felix's account after 21 years :</u>
The formula used here is,
⇒ 
where A is the amount after 21 years.
- P is the initial amount deposited ⇒ P = 2000
- r is the rate ⇒ r = 0.06
- n is the number of times interest is compounded per year⇒ n = 1
- t is the time period ⇒ t = 21
⇒ 
⇒ 
⇒ 
⇒ 
Therefore, The money in the Felix's account will be $6798 when he is 21.
Answer:
um i dont know
Step-by-step explanation:
<span> -y - 5 + 3y + 2
= 2y - 3
-----------------------</span>