Answer:
x = 10 or x = 2
Step-by-step explanation:
Solve for x:
x^2 - 12 x + 20 = 0
Hint: | Solve the quadratic equation by completing the square.
Subtract 20 from both sides:
x^2 - 12 x = -20
Hint: | Take one half of the coefficient of x and square it, then add it to both sides.
Add 36 to both sides:
x^2 - 12 x + 36 = 16
Hint: | Factor the left hand side.
Write the left hand side as a square:
(x - 6)^2 = 16
Hint: | Eliminate the exponent on the left hand side.
Take the square root of both sides:
x - 6 = 4 or x - 6 = -4
Hint: | Look at the first equation: Solve for x.
Add 6 to both sides:
x = 10 or x - 6 = -4
Hint: | Look at the second equation: Solve for x.
Add 6 to both sides:
Answer: x = 10 or x = 2
Answer:
a
Step-by-step explanation:
theres a 90 degree angle and a has a 95 so thats pretty close
Answer:
1.- He received 388 dollars in exchange.
2.-(100 x 4) - (7.00 + 5.00)
= 400 - 12
= 488
3.- I buy 15 basketballs.
And I buy 6 soccer balls.
4.- (135 ÷ 9) (48 ÷ 8)
= 15, 6
Step-by-step explanation:
I hope I have helped you can you put that this is the smartest answer please?
Answer:
The population standard deviation is not known.
90% Confidence interval by T₁₀-distribution: (38.3, 53.7).
Step-by-step explanation:
The "standard deviation" of $14 comes from a survey. In other words, the true population standard deviation is not known, and the $14 here is an estimate. Thus, find the confidence interval with the Student t-distribution. The sample size is 11. The degree of freedom is thus
.
Start by finding 1/2 the width of this confidence interval. The confidence level of this interval is 90%. In other words, the area under the bell curve within this interval is 0.90. However, this curve is symmetric. As a result,
- The area to the left of the lower end of the interval shall be
. - The area to the left of the upper end of the interval shall be
.
Look up the t-score of the upper end on an inverse t-table. Focus on the entry with
- a degree of freedom of 10, and
- a cumulative probability of 0.95.
.
This value can also be found with technology.
The formula for 1/2 the width of a confidence interval where standard deviation is unknown (only an estimate) is:
,
where
is the t-score at the upper end of the interval,
is the unbiased estimate for the standard deviation, and
is the sample size.
For this confidence interval:
Hence the width of the 90% confidence interval is
.
The confidence interval is centered at the unbiased estimate of the population mean. The 90% confidence interval will be approximately:
.