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alukav5142 [94]
3 years ago
10

A ball is thrown in the air from a ledge. Its height in feet is represented by f(x) = –16(x2 – 7x – 8), where x is the number of

seconds since the ball has been thrown. The height of the ball is 0 feet when it hits the ground. How many seconds does it take the ball to reach the ground?
Mathematics
2 answers:
lbvjy [14]3 years ago
8 0
f(x)=-16( x^{2} -7x-8)

is the functions that determines the height of the ball in Feet, after x seconds being thrown.

so for example to calculate how many feet above the ground in the ball 5 seconds after being thrown, we calculate f(5)

f(5)=-16( 5^{2} -7*5-8)=-16(25-35-8)=-16(-18)=288 feet

to solve our problem we need to find x such that f(x)=0

so we solve :

-16( x^{2} -7x-8)=0

x^{2} -7x-8=0

using the quadratic formula, le a=1, b=-7, c=-8

\sqrt{D} = \sqrt{ b^{2}-4ac}= \sqrt{ (-7)^{2}-4(1)(-8) }= \sqrt{49+32}= \sqrt{81}=9

so 

x_1= \frac{-b+ \sqrt{D} }{2a}= \frac{7+9}{2}= \frac{16}{2}=8

x_1= \frac{-b- \sqrt{D} }{2a}= \frac{7-9}{2}= \frac{-2}{2}=-1, which cannot be the solution to our problem.


Answer: 8 s
iren [92.7K]3 years ago
7 0

You are right thanks

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Answer:

No.

Step-by-step explanation:

The triangle inequality theorem states that the sum of two sides of a triangle must be greater than the third side.

5 + 8 = 13.

13, which is the sum of two sides, is not larger than 16, the third side.

Therefore, a triangle cannot have these side lengths.

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Find the x intercept and the y intercept of the graph of the equation <br> 2x+4y=8
maksim [4K]

Answer:

x-intercept: 4

y-intercept: 2

Step-by-step explanation:

finding the x-intercept:

first, substitute y = 0.

2x + 4 x 0 = 8

then, remove the 0.

2x + 0 = 8

then, divide both sides. 2x = 8

so, x = 4.

finding the y-intercept:

first, substitute x = 0.

then, solve.

2 x 0 + 4y = 8

so, y = 2.

3 0
3 years ago
Number 15 really need help
Leokris [45]
$9 a day for 8 days.

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So!

$9 * 8days

Or you can also think of it as this: 
9+9+9+9+9+9+9+9

Our answer comes out to be 72! 
8 0
3 years ago
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please help :{ brainliest if you can get it right and I need you to prove why your answer is correct, thanksss​
beks73 [17]

Answer:

The Value of a=\frac{15}{4}.

Step-by-step explanation:

We have Named the figure please find the attachment for your reference.

Given:

PR = y

QR = a

RS = b

PS = z

PQ = x

QS = 15

∠P = 90°

∠R = 90°

∠Q = 60°

∠S = 30°

We need to find the Value of 'a'.

Solution:

Now we know that:

In Δ PQS

∠P = 90°

∠S = 30°

Now we know that;

sin\ \theta = \frac{opposite\ side}{Hypotenuse}

sin \ S= \frac{PQ}{QS}

Substituting the given values we get;

sin\ 30\°=\frac{x}{15}

Now we know that;

sin\ 30\° = \frac12

So we can say that;

\frac{1}{2}=\frac{x}{15}\\\\x=\frac{15}{2}

Now In Triangle PQR.

∠R = 90°

∠Q = 60°

So we can say that;

Cos \theta = \frac{adjacent \ Side}{Hypotenuse}\\

Cos\ Q = \frac{QR}{PQ}

Substituting the given values we get;

cos 60\°= \frac{a}{x}

Now we know that;

cos 60\°= \frac12

x=\frac{15}{2}

So substituting the values we get;

\frac{1}{2}=\frac{a}{\frac{15}{2}}

By Using Cross Multiplication we get;

a= \frac{1}{2}\times\frac{15}{2}\\\\a=\frac{15}{4}

Hence The Value of a=\frac{15}{4}.

6 0
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What is the solution to this inequality: -4(3x-5)&lt;2(3x+4)​
Delicious77 [7]

Answer:

x > 2/3

Step-by-step explanation:

-4(3x - 5) < 2(3x + 4)​

Divide both sides by 2.

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Distribute on the left side.

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Subtract 3x from both sides.

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Subtract 10 from both sides.

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Divide both sides by -9. Remember that when you divide both sides of an inequality by a negative number, the inequality sign changes direction.

x > (-6)/(-9)

x > 6/9

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7 0
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