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DanielleElmas [232]
3 years ago
13

Solve the equation. x2 18x 81 = 25 a. 14, 4 b. –4, –14 c. 14, –14 d. –4, 4

Mathematics
2 answers:
Snowcat [4.5K]3 years ago
7 0

Answer:

The answer is the option B

-4,-14

Step-by-step explanation:

we know that

The formula to solve a quadratic equation of the form ax^{2} +bx+c=0 is equal to

x=\frac{-b(+/-)\sqrt{b^{2}-4ac}} {2a}

in this problem we have

x^{2}+18x+81=25  

x^{2}+18x+56=0  

so

a=1\\b=18\\c=56

substitute in the formula

x=\frac{-18(+/-)\sqrt{18^{2}-4(1)(56)}} {2(1)}

x=\frac{-18(+/-)\sqrt{100}} {2}

x=\frac{-18(+/-)10} {2}

x1=\frac{-18+10} {2}=-4

x2=\frac{-18-10} {2}=-14

Ivahew [28]3 years ago
3 0

Answer:

The correct option is B. -4 , -14  

Step-by-step explanation:

The equation is given to be : x² + 18x + 81 = 25

We need to find the roots of this given equation

⇒ x² + 18x + 81 = 25

⇒ x² + 18x + 81 - 25 = 0

⇒ x² + 18x + 56 = 0

⇒ x² + 14x + 4x + 56 = 0

⇒ x( x + 14) + 4( x + 14) = 0

⇒ (x + 14) · (x + 4) = 0

⇒ x = -14 or x = -4

Therefore, The correct option is B. -4 , -14

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The maximum value of 12 sin 0-9 sin²0 is: -​
jeka57 [31]

Answer:

4

Step-by-step explanation:

The question is not clear. You have indicated the original function as 12sin(0) - 9sin²(0)

If so, the solution is trivial. At 0, sin(0) is 0 so the solution is 0

However, I will assume you meant the angle to be \theta rather than 0 which makes sense and proceed accordingly

We can find the maximum or minimum of any function by finding the first derivate and setting it equal to 0

The original function is

f(\theta) = 12sin(\theta) - 9 sin^2(\theta)

Taking the first derivative of this with respect to \theta and setting it equal to 0 lets us solve for the maximum (or minimum) value

The first derivative of f(\theta) w.r.t \theta is

                        12\cos\left(\theta\right)-18\cos\left(\theta\right)\sin\left(\theta\right)

And setting this = 0 gives

12\cos\left(\theta\right)-18\cos\left(\theta\right)\sin\left(\theta\right) = 0

Eliminating cos(\theta) on both sides and solving for sin(\theta) gives us

sin(\theta) = \frac{12}{18} = \frac{2}{3}

Plugging this value of sin(\theta) into the original equation gives us

12(\frac{2}{3}) - 9(\frac{4}{9} ) = 8 - 4 = 4

This is the maximum value that the function can acquire. The attached graph shows this as correct

3 0
2 years ago
Please help. i don't understand
zaharov [31]

78×.33=25.74 busses are new

25.74+15=40.74 new busses

78+15=93 total busses

40.74/78=0.5223076923= 52% will be new with the new 15 busses

4 0
3 years ago
If (6^0)^x= 1 what are the possible outcomes of x? Explain your answer.
swat32
X can be any  real number 

As long as it is to the power of 0, it will equal one. And because 6^0 = 1, 1^x can be any positive number, and it will still give you one.

As stated by WojtekR, even negative numbers can get 1

x = - 5

(6^0)^-5 =  1^-5 = 1/1 = 1


~ Thanks @WojtekR
7 0
3 years ago
You have a 20% increase with a 25% decrease? what do i do
anzhelika [568]

Answer:

Decrease by 5%

4 0
3 years ago
Alice is baking a cake. She doesn’t intend to eat it, but tells you half of what you find is yours. She tells the same thing to
tankabanditka [31]

Answer: a) P = 0.5, b) P = 0.07

Step-by-step explanation:

Hi!

Lets call X₁ the time at which you arrive, and X₂ the time at which Bob arrives. Both are random variables with uniform density in the interval [0, 60] (in minutes). Their joint distribuition is uniform over the square in the image, with value P = 1/(60*60) = 1/3600.

a) For you to get more cake than Bob, you should arrive earlier. This event is A = { X₁ < X₂ }, the shaded triangle in the figure.The area of this event (set) is half the total area of the square, so P(A) = 0.5.

It makes sense, beacuse its equally probable for you or Bob to arrive earlier, as both have uniform density over the time interval.

b) In this case you arrive later than Bob, but less than 5 minutes later. So the event is B = { X₂ < X₁ < (X₂ + 5) } . This is the gray shaded area in b) part of the image. Its area is the difference two triangles (half square - blue triangle), then the probability is:

P(B) = 0.5 - \frac{(0.5*55^2)}{3600} =0.07

7 0
4 years ago
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