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3 years ago

4. For each equation, determine if =-2 is a solution. Explain or show your reasoning.

Mathematics

1 answer:

Aneli [31]3 years ago

6 0

Answer:

a. 14 b. -2

Step-by-step explanation:

a. 10=2x-18

28=2x ; x=14

b. 3x+12=2x+6+4

3x+12=2x+10

x=-2

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Use the exponential decay model, Upper A equals Upper A 0 e Superscript kt, to solve the following. The half-life of a certai

Akimi4 [234]

Answer:

It will take 7 years ( approx )

Step-by-step explanation:

Given equation that shows the amount of the substance after t years,

$A=A_0 e^{kt}$

Where,

$A_0$ = Initial amount of the substance,

If the half life of the substance is 19 years,

Then if t = 19, amount of the substance = $\frac{A_0}{2}$ ,

i.e.

$\frac{A_0}{2}=A_0 e^{19k}$

$\frac{1}{2} = e^{19k}$

$0.5 = e^{19k}$

Taking ln both sides,

$\ln(0.5) = \ln(e^{19k})$

$\ln(0.5) = 19k$

$\implies k = \frac{\ln(0.5)}{19}\approx -0.03648$

Now, if the substance to decay to 78% of its original amount,

Then $A=78\% \text{ of }A_0 =\frac{78A_0}{100}=0.78 A_0$

$0.78 A_0=A_0 e^{-0.03648t}$

$0.78 = e^{-0.03648t}$

Again taking ln both sides,

$\ln(0.78) = -0.03648t$

$-0.24846=-0.03648t$

$\implies t = \frac{0.24846}{0.03648}=6.81085\approx 7$

Hence, approximately the substance would be 78% of its initial value after 7 years.

5 0

3 years ago

Which of the following is the complete factorization of 3x2-6x-240?

AURORKA [14]

1. Reduce <span>3x2-6x-240 to x^2 - 2x - 80

2. Use " ^ " to indicate exponentiation

3. Factor </span>x^2 - 2x - 80 using completing the square:

x^2 - 2x + 1^2 - 1^2 - 80

(x+1)^2 - 1 - 80
(x+1)^2 - 81
(x+1)^2 - 9^2 = (x+1-9)(x+1 +9), or (x-8)(x+10)

Final answer, with all factors shown: 3(x-8)(x+10)

4 0

3 years ago

HELP PLEASE!! I need help

chubhunter [2.5K]

Answer:

$C=5.25+2.50x$

Step-by-step explanation:

It starts with a base cost of $5.25 and increases by $2.50 for every ticket sold. Add 2.50(number of tickets) to the admission cost to get the total cost.

4 0

3 years ago

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Find the y intercept of 2x - 5y + 7 = 0

Tanya [424]

The answer is in the picture below have a good day :)