Help please. really need answers to understand

hmmmm.... each question here is relatively straight forward, the issue is that these questions basically represent an entire unit (possible two) of an Algebra II class... I can provide answers, but the explanation (if you don't know the basic ideas might be elusive, But I will try to help)

Step-by-step explanation:

1) A = P (1+ r/n) ^ nt

interest equation ... monthly compounding so n = 12 thus r gets divided by 12 and t get multiplied by 12

A = 10,000(1 + .04/12)^(3*12)

A = 10000(1.00333)^36

A = $11,272.71

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2)  

A = 15,000

18,000= 15,000

1.2=

ln(1.2) = .06t (ln e)

.1823 / .06 = 3.03 years

Note: ln e = 1

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thus: 5x+ 1 = 3

5x = 2

x = 2/5

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f(x) = 5x - 12

y = 5x - 12

inverse

x = 5y - 12

5y = x + 12

y = 1/5 x + 12/5

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fog(X) =

f(X) =6x+12

g(x) = x^2 + 3

fog(X) = 6(x^2 + 3)+12

           = 6x^2 + 18 + 12

            = 8x^2 + 30

Domain (- infinity, + infinity)

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vertex 3x^2 - 6x + 2

verted = [-b/2a, f(-b/2a)]

a=3 , b=-6 , c = 2

-b/2a = 6/6 = 1

f(-b/2a) = -1

vertex = (1,-1)

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30x - .4x^2

-30/-.8 = 37.5

max rev =  30(37.5) - .4(37.5)^2 = $562.5