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Alinara [238K]
3 years ago
10

Solve by completing the square: x^2 + 3x - 9 = 0

Mathematics
2 answers:
tekilochka [14]3 years ago
6 0

Answer:

Step-by-step explanation:

x^2 + 3x - 9 =0

By comparing with the equation ax^2+bx+c = 0,

we get,

a = 1, b=3, c = -9

we know the formula for x is,

x = (-b±√(b^2 - 4ac))/2a

x = (-3±√45)/2

x = (-3±3√5)/2

x = (-3+3√5)/2, (-3-3√5)/2

My name is Ann [436]3 years ago
3 0

Answer:

2 solutions. x = -3/2 + 3/2 * sqrt(5) and x = -3/2 + -3/2 * sqrt(5)

Step-by-step explanation:

<h3>Let's solve your equation step by step.</h3>

x^2 + 3x −9 = 0

For this equation: a=1, b=3, c=-9

1x^2 + 3x+ −9 = 0

Step 1: Use quadratic formula with a=1, b=3, c=-9.

x = (-b ± \sqrt{b^2 - 4ac})/2a

x = (-3 ± \sqrt{3^2 - 4(1)(-9)})/2a

x = (-3 ± \sqrt{45})/2

x = -3/2 + 3/2 * sqrt(5) or x = -3/2 + -3/2 * sqrt(5)

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An electric sale gives a reading equal to the true weight plus a random error that isnormally distributed with mean 0 and standa
Pepsi [2]

Answer:

a) 95% confidence interval estimate of the true weight is (3.026, 3.274)

b) 99% confidence interval estimate of the true weight is (2.944, 3.356)

Step-by-step explanation:

Confidence Interval can be calculated using M±ME where

  • M is the mean of five successive weightings (3.150)
  • ME is the margin of error from the mean

And margin of error (ME) can be calculated using the formula

ME=\frac{t*s}{\sqrt{N} } where

  • t is the corresponding statistic in the given confidence level and degrees of freedom(t-score)
  • s is the standard deviation of the random error (0.1)
  • N is the sample size (5)

Using the numbers 95% confidence interval estimate of the true weight is:

3.150±\frac{2.776*0.1}{\sqrt{5} }≈3.150±0.124

And 99% confidence interval estimate of the true weight is:

3.150±\frac{4.604*0.1}{\sqrt{5} }≈3.150±0.206

3 0
3 years ago
If the median were to be calculated at 82.5 degrees, then would the feasible mean be 81.6?
dmitriy555 [2]
I think your right,It would be 81.6.
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7 0
3 years ago
:) PLEASE!!!! HELP! some food while you solve &lt;3
Dominik [7]

Answer:

1/3

Step-by-step explanation:

rise over run. Find two places that land on a line I picked (0,0) and (3,1) then count up one from the first point and over 3 for the second.

6 0
3 years ago
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omeli [17]
A) n x 2.0
b) n x 2.0 = y

Hope this helps :)
8 0
3 years ago
The question is:
Naddik [55]

Answer:

2.5 gallons of the 20% solution must be replaced by the 36% solution.

Step-by-step explanation:

.12(20 - x) + .36x = 20(.15)

2.4 - .12x + .36x = 3

2.4 - .24x = 3

- .24x =  - .6

.24x = .6

x = 2.5

7 0
1 year ago
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