Answer:
f=40
Step-by-step explanation:
f=28, a=7

Hope that this is helpful.
Have a nice day.
Solve the equation for x by finding a, b, and c of the quadratic then applying the quadratic formula.
x = 7,3
Okay, so the equations would be:
x + 3y = 24
3y + 5x = 36
Imma use Substitution to solve this:
x = -3y + 24
3y + 5(-3y + 24) = 36
3y - 15y + 120 = 36
-12y + 120 = 36
-12y = -84
y = 7
x = -3(7) + 24
x = -21 + 24
x = 3
So the first number (x) would be 3 and the second number (y) would be 7.
The answer is definitely c
Answer: 6.93 years
Step-by-step explanation:
Given
Rate of interest is 
Future value is given by 
For the investment to double itself, i.e. 

It takes around 6.93 years to double the investment.