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2 years ago

Solve x2 - 8x - 9 = 0. Rewrite the equation so that it is of the form x2 + bx = c.

Mathematics

2 answers:

barxatty [35]2 years ago

4 0

Answer:

x=9,-1 and $x^2+(-8)x=9$

Explanation:

we have been given with the quadratic equation $x^2-8x-9$

we compare the given quadratic equation with general quadratic equation

general quadratic is $ax^2+bx+c=0$

from given quadratic equation a=1,b= -8,c= -9

substituting these values in the formula for discriminant $D=b^{2}-4ac$

$D=(-8)^2-4(1)(-9)=100$

Now, to find the value of x

Formula is $x=\frac{-b\pm\sqrt{D}}{2a}$

Now, substituting the values we will get

$x=\frac{-(-8)\pm\sqrt{100}} {2}= \frac{8\pm10}{2}=9,-1$

And rewritting the given equation by shifting 9 to right hand side of the given equation and taking minus inside the bracket so as to convert it in the form of

$x^2+bx=c$

sweet [91]2 years ago

4 0

It can be noted from the given that a = 1, b = -8 and c = -9. To transpose c to the other side of the equation, all that needs to be done is to add 9 to both sides of the equation,
x² - 8x -9 + 9 = 0 + 9
The answer would be,
x² - 8x = 9

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A survey of 132 students is selected randomly on a large university campus. They are asked if they use a laptop in class to take

ddd [48]

Answer:

For 90% CI = (0.428, 0.572)

For 98% CI = (0.399, 0.601)

The confidence interval (and Margin of error) reduces when 90% confidence level is used compared to when 98% confidence level is used.

Step-by-step explanation:

Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.

The confidence interval of a statistical data can be written as.

p+/-z√(p(1-p)/n)

Given that;

Proportion p = 66/132 = 0.50

Number of samples n = 132

Confidence level = 90%

z(at 90% confidence) = 1.645

Substituting the values we have;

0.50 +/- 1.645√(0.50(1-0.50)/132)

0.50 +/- 1.645√(0.001893939393)

0.50 +/- 0.071589436011

0.50 +/- 0.072

(0.428, 0.572)

The 90% confidence level estimate of the true population proportion of students who responded "yes" is (0.428, 0.572)

For 90% CI = (0.428, 0.572)

For 98% CI = (0.399, 0.601)

The confidence interval (and Margin of error) reduces when 90% confidence level is used compared to when 98% confidence level is used.

7 0

2 years ago

11/12−6/1q+6/5q−3/1, Combine like terms to create an equivalent expression.

Nikolay [14]

Answer: $-\frac{25}{12} -\frac{24q}{5}$

Step-by-step explanation:

$\frac{11}{12} -\frac{6}{1} q+\frac{6}{5}q-\frac{3}{1}$

$\frac{11}{12} -6q+ \frac{6q}{5} -\frac{3}{1}$

$\frac{11}{12}-6q \frac{6q}{5} -3$

$(\frac{11}{12} -3)+(-6q+\frac{6q}{5} )$

$-\frac{25}{12}- \frac{24q}{5}$

Simplify three times, collect like terms and simplify again, how to collect like terms see their differences and then put them into groups, for example I put all the numbers without variables on one side and all the numbers with variables on another.

Hope this helps, now you know the answer and how to do it. HAVE A BLESSED AND WONDERFUL DAY! As well as a great rest of Black History Month! :-)

- Cutiepatutie ☺❀❤

4 0

2 years ago

Read 2 more answers

The shoe store manager borrowed $17,000.00 from the bank to purchase 1000 pairs of shoes. The bank charges a simple interest rat

-Dominant- [34]

Answer:

2550

Step-by-step explanation:

1) So he borrowed 17,000

2) Simple interest is 5%

3) so 0.05 *17000 = 850

4)It takes the manager 3 years so, 850*3=2550

5) so 2550 is the total amount of interest the manager needs to pay

7 0

1 year ago

On tuesday the value of stock decreased by 1/2 point. On Wednesday, the value increased by 3/4 point. On thursday the value decr

zhenek [66]

1 whole is the awnser because it would be 10\10 and if you simplify you get l whole

3 0

2 years ago

Approximate the area under the curve y = x² from x = 2 to x = 5 using a Right Endpoint approximation with 6 subdivisions.

Tanzania [10]

Answer:

$\text{Area}\,=36.75$

Step-by-step explanation:

Using right estimation point simply means to form a bunch of rectangles between the two limits, x =2 and x = 5. and add the areas of all those rectangles.

There must be 6 subdivisions between 2 and 5. so, to do that:

$\Delta{x}=\dfrac{5-2}{6}=0.5$

the length of each subdivision is 0.5 units. That also means that the 6 rectangles in between the limits will each have the base length of 0.5 units.

So the endpoints of each subdivision from 3 to 5 will be:

$\begin{tabular}{|c|c|c|c|c|}3&3.5&4&4.5&5\\\end{tabular}$

By <em>right </em>endpoint approx<em>, </em>we mean that the height of the rectangles will be determined by the right endpoint of each subdivision, that is, it must be equal to the function value of the first limit.

$\begin{tabular}{|c|c|c|}subdivision&$x$&height($y=x^2$)&3 to 3.5&3.5&12.25&3.5 to 4&4&16&4 to 4.5&4.5&20.25&4.5 to 5&5&25\end$

Note that we have used the right-end-point of the subdivision to determine the height the rectangles.

All that's left to do now is to simply calculate the areas of the each of the rectangles. And add them up.

the base of each of the rectangle is $\Delta{x}=0.5$

and the height is determined in the table above.

$\text{Area}\,=(0.5\times12.25)+(0.5\times16)+(0.5\times20.25)+(0.5\times25)$

$\text{Area}\,=0.5(12.25+16+20.25+25)$

$\text{Area}\,=36.75$

3 0

2 years ago