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Sunny_sXe [5.5K]
4 years ago
13

Which is a solution to the equation? (x −2)(x + 5) = 18

Mathematics
2 answers:
Alik [6]4 years ago
5 0
(x-2)(x+5)=18
x²+3x-10=18
Subtract 18 to each side
x²+3x-10-18=18-18
x²+3x-28=0
x²+7x-4x-28=0
x(x+7)-4(x+7)=0
(x-4)(x+7)=0

x-4=0
Add 4 to each side
x-4+4=0+4
x=4

x+7=0
Subtract 7 to each side
x+7-7=0-7
x=-7. As a result,the solutions to this equation are 4 and -7. Hope it help!
kifflom [539]4 years ago
4 0
Well if finding X you get 4,-7 when you simplify the whole equation you get that as well.
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Solve using the quadratic formula. Show all work. Write each solution in simplest form. No decimals.
alexira [117]

Answer:

Option B

Step-by-step explanation:

Given quadratic equation is,

12a² + 9a + 7 = 0

By comparing this equation with standard quadratic equation,

hx² + kx + c = 0

h = 12, k = 9 and c = 7

By using quadratic formula,

a = \frac{-k\pm\sqrt{k^2-4hc}}{2h}

  = \frac{-9\pm\sqrt{9^2-4(12)(7)}}{2(12)}

  = \frac{-9\pm\sqrt{81-336}}{2(12)}

  = \frac{-9\pm\sqrt{-255}}{24}

  = \frac{-9\pm i\sqrt{255}}{24}

a = \frac{-9+ i\sqrt{255}}{24},\frac{-9- i\sqrt{255}}{24}

Therefore, Option B will be the correct option.

3 0
3 years ago
From 75 pencil to 225 pencils. Round to the nearest percent.
MatroZZZ [7]
For finding percents, I use a method called FOO
which is final-original÷original
the original is the first number and the final is the second
After FOO you must multiply by 100 to make it a percent
The equation is as followed:
225-75÷75×100
The answer is 125%
4 0
3 years ago
Read 2 more answers
Tina wants to save money for school. Tina invests $400 in an account that pays an interest rate of 7.5%.
Over [174]
Here's the given:
P=$400
i=7.5%
A=$8500

The formula used for this problem is:
A = P(1+i)^t

Manipulating the equation to arrive at t, we have:
t = ln(A/P) / ln(1+i)

Plugging in values:
t = ln($8500/$400) / ln(1+0.075)
<span>t = 42.26 years</span>
7 0
3 years ago
⦁ The population of the Tallahassee metropolitan area was 382,627 at the end of 2017 with a growth rate of 2.78%. Using the expo
a_sh-v [17]

Answer:

The exponential growth model for the population of the Tallahassee metropolitan area is y=382627(1.0278)^t.

Step-by-step explanation:

The exponential formula is

y=b(1+r)^t

Where b is initial population, r is growth rate, (1+r) is growth factor and t is time (in years) after the initial year.

The population of the Tallahassee metropolitan area was 382,627 at the end of 2017. The growth rate is 2.78%.

Here the initial year is 2017 and rate is 0.0278

y=382627(1+0.0278)^t

y=382627(1.0278)^t

Graph of the equation is shown below. The x-axis represents the number of years after 2017 and y-axis represents the total population.

Difference between 2025 and 2017 is 8 years. Put t=8

y=382627(1.0278)^8

y=382627(1.0278)^8

y=476479.828188\approx 476479

Therefore the projected population in 2025 is 476479.

7 0
4 years ago
How long will it take for an investment to triple if it is compounded continuously at 12%
myrzilka [38]

Answer:

9.694 years

Step-by-step explanation:

Let the investment is $P.

So, we are asked to determine the time it will grow to triple with the compound interest rate of 12%.

Let the time is y years.

So, from the formula of compound interest we can write

3P = P(1 + \frac{12}{100} )^{y}

⇒ (1 + \frac{12}{100} )^{y} = 3

⇒ (1.12)^{y} = 3

Now, taking log both sides we get,

y log 1.12 = log 3 {Since, \log a^{b} = b \log a }

⇒ 0.04922y = 0.477712

⇒ y = 9.694 years (Answer)

3 0
3 years ago
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