Can anyone help me out? I’ll give Brainly!! 5,175 isn’t correct :(

Solve by completing the square <br><br> 3x^2-7x-1

docker41 [41]

Answer:

$x=\frac{7+\sqrt{61}}{6},\:x=\frac{7-\sqrt{61}}{6}$

Step-by-step explanation:

$a=3,\:b=-7,\:c=-1:\quad x_{1,\:2}=\frac{-\left(-7\right)\pm \sqrt{\left(-7\right)^2-4\cdot \:3\left(-1\right)}}{2\cdot \:3}$

$x=\frac{7+\sqrt{61}}{6},\:x=\frac{7-\sqrt{61}}{6}$

3 0

3 years ago

Select the correct answer from the drop-down menu. A vertical pole is supported by two ropes staked to the ground on opposite si

Ainat [17]

Answer:

6.78 m

Step-by-step explanation:

Since the set up forms a triangle with length of ropes two sides of the triangle a = 8 m and b = 7 m respectively, the distance between them which is c = 6 m forms the third side of the triangle.

To find the height of the pole, we need to find the angle between any of the ropes and the ground. So, choosing the 8 m long rope side and using the cosine rule,

b² = a² + c² - 2accosФ where Ф is the angle opposite the 7 m long side which is also the angle between the 8 m long side and the ground.

So, making, Ф subject of the formula, we have

b² - (a² + c²) = 2accosФ

cosФ = [b² - (a² + c²)]/2ac

Ф = cos⁻¹{[b² - (a² + c²)]/2ac}

substituting the values of the variables into the equation, we have

Ф = cos⁻¹{[b² - (a² + c²)]/2ac}

Ф = cos⁻¹{[7² - (8² + 6²)]/2(8)(6)}

Ф = cos⁻¹{[49 - (64 + 36)]/96}

Ф = cos⁻¹{[49 - 100]/96}

Ф = cos⁻¹{-51/96}

Ф = cos⁻¹{-0.53125}

Ф = 122.09°

Since the height of the pole, h is a perpendicular bisector to the base of the triangle, and the 8 m long side form a triangle with it and the ground and the 8 m long side being the hypotenuse side of this triangle, we have that

sinФ = h/a where a = 8 m and Ф = 122.09° = the angle between the 8 m long side and the ground.

h = asinФ

substituting the values of the variables into the equation, we have

h = asinФ

h = (8 m)sin122.09°

h = 8 m × 0.8472

h = 6.78 m

3 0

3 years ago

A number has the same digit in its hundreds place and its hundredths place. How many times greater is the value of the digit in

Free_Kalibri [48]

Answer:

A number has the same digit in its hundreds place and its hundredths place. Let the digit be '1'. Hence, the the value of the digit in the hundreds place is 10,000 times greater than the value of the digit in the hundredths place

Step-by-step explanation:

5 0

3 years ago

Is this the right answer?,please help before I turn it in

astraxan [27]

Yes it’s the right answer, I just did it myself and I got -4

5 0

3 years ago

You roll 2 dice. If the sum of the dice is: 2, 3, 4 you win $20. If the sum is 5, 6, 7, 8 you win $10. If the sum is 9, 10, 11 y

Elis [28]

Answer:

1) The expected value of the "winnings" is $(-0.97 $\overline 2$ )

2) The variance for the "winnings" is $0.57966

3) The standard deviation for the "winnings" is$0.761354

4) The game is not a fair game because one is expected to lose $0.97 $\overline 2$

Step-by-step explanation:

1) The probability of having a sum of 2 = 1/6×1/6 = 1/36

The probability of having a sum of 3 = 1/6×1/6 = 1/36

The probability of having a sum of 4 = 1/6×1/6 + 1/6×1/6 = 1/18

The probability of having a sum of 5 = 1/6×1/6 + 1/6×1/6 = 1/18

The probability of having a sum of 6 = 1/6×1/6 + 1/6×1/6 + 1/6×1/6 = 1/12

The probability of having a sum of 7 = 1/6×1/6 + 1/6×1/6 + 1/6×1/6 = 1/12

The probability of having a sum of 8 = 1/6×1/6 + 1/6×1/6 + 1/6×1/6 = 1/12

The probability of having a sum of 9 = 1/6×1/6 + 1/6×1/6 = 1/18

The probability of having a sum of 10 = 1/6×1/6 + 1/6×1/6 = 1/18

The probability of having a sum of 11 = 1/6×1/6 = 1/36

The probability of having a sum of 12 = 1/6×1/6 = 1/36

The values are;

For 2, we have 1/36 × (20 - 5) = 0.41 $\overline 6$

For 3, we have 1/36 × (20 - 5) = 0.41 $\overline 6$

For 4, we have 1/18 × (20 - 5) = 0.8 $\overline 3$

For 5, we have 1/18 × (10 - 5) = 0.2 $\overline 7$

For 6, we have 1/12 × (10 - 5) = 0.41 $\overline 6$

For 7, we have 1/12 × (10 - 5) = 0.41 $\overline 6$

For 8, we have 1/12 × (10 - 5) = 0.41 $\overline 6$

For 9, we have 1/18 × (-20 - 5) = -1.3 $\overline 8$

For 10, we have 1/18 × (-20 - 5) = -1.3 $\overline 8$

For 11, we have 1/36 × (-20 - 5) = -0.69 $\overline 4$

For 12, we have 1/36 × (-25 - 5) = -0.69 $\overline 4$

The expected value of the winnings is given as follows;

0.41 $\overline 6$ + 0.41 $\overline 6$ + 0.8 $\overline 3$ + 0.8 $\overline 3$ + 0.8 $\overline 3$ + 0.41 $\overline 6$ + 0.41 $\overline 6$ + -1.3 $\overline 8$ -1.3 - 0.69 $\overline 4$ - 0.69 $\overline 4$ = -0.97 $\overline 2$

Therefore, the expected value = $-0.97 $\overline 2$ , which is one is expected to lose $0.97 $\overline 2$

2) Using Microsoft Excel, we have;

The variance for the "winnings", σ² = $0.57966

3) The standard deviation for the "winnings" = √σ² = √(0.57966) ≈ $0.761354

4) The game is not a fair game because one is expected to lose $0.97 $\overline 2$

3 0

3 years ago