Solve x2-4x-7=0 by completing the square
2 answers:
HEY mate here is pratyush from India for your help...
the answer is with the attachment
hope it helps you..
the answer is with the attachment
hope it helps you..
Answer:
x = 2 ±
Step-by-step explanation:
Given
x² - 4x - 7 = 0 ( add 7 to both sides )
x² - 4x = 7
To complete the square
add (half the coefficient of the x- term)² to both sides
x² + 2(- 2)x + (- 2)² = 7 + (- 2)²
(x - 2)² = 7 + 4 = 11 ( take the square root of both sides )
x - 2 = ± ( add 2 to both sides )
x = 2 ± ← exact solutions
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Step-by-step explanation:
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Answer:
92.9997<<99.5203
Step-by-step explanation:
Using the formula for calculating the confidence interval expressed as:
CI = xbar ± Z * S/√n where;
xbar is the sample mean
Z is the z-score at 90% confidence interval
S is the sample standard deviation
n is the sample size
Given parameters
xbar = 96.52
Z at 90% CI = 1.645
S = 10.70.
n = 25
Required
90% confidence interval for the population mean using the sample data.
Substituting the given parameters into the formula, we will have;
CI = 96.52 ± (1.645 * 10.70/√25)
CI = 96.52 ± (1.645 * 10.70/5)
CI = 96.52 ± (1.645 * 2.14)
CI = 96.52 ± (3.5203)
CI = (96.52-3.5203, 96.52+3.5203)
CI = (92.9997, 99.5203)
<em>Hence a 90% confidence interval for the population mean using this sample data is 92.9997<</em><em><99.5203</em>