1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kirill [66]
2 years ago
15

Solve x^2-8x-9=0 using completing the square (show the work)

Mathematics
1 answer:
Elden [556K]2 years ago
3 0

Answer: x=9,-1

Step-by-step explanation:

First, we are gonna start out with finding two numbers that multiply to equal -9 and add up to equal -8

Those numbers would be -9 & 1

-9+1=-8

-9x1=-9

Now we have

(x-9)(x+1)

x-9=0   x+1=0

 +9 +9   -1  -1

x=9      x=-1

You might be interested in
Suppose we are testing the null hypothesis H 0 mu=20 and the alternative H iu =20 , normal population with sigma=6 A random samp
cupoosta [38]

Answer:

The value of the test statistic is z = -1.5

Step-by-step explanation:

The formula for the test statistic is:

z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}

In which X is the statistic, \mu is the mean, \sigma is the standard deviation and n is the number of observations.

In this problem, we have that:

\mu = 20, X = 17, \sigma = 6, n = 9

So

z = \frac{X - \mu}{\frac{\sigma}{\sqrt{n}}}

z = \frac{17 - 20}{\frac{6}{\sqrt{3}}}

z = -1.5

The value of the test statistic is z = -1.5

8 0
3 years ago
a. Fill in the midpoint of each class in the column provided. b. Enter the midpoints in L1 and the frequencies in L2, and use 1-
Tresset [83]

Answer:

\begin{array}{ccc}{Midpoint} & {Class} & {Frequency} & {64} & {63-65} & {1}  & {67} & {66-68} & {11} & {70} & {69-71} & {8} &{73} & {72-74} & {7}  & {76} & {75-77} & {3} & {79} & {78-80} & {1}\ \end{array}

Using the frequency distribution, I found the mean height to be 70.2903 with a standard deviation of 3.5795

Step-by-step explanation:

Given

See attachment for class

Solving (a): Fill the midpoint of each class.

Midpoint (M) is calculated as:

M = \frac{1}{2}(Lower + Upper)

Where

Lower \to Lower class interval

Upper \to Upper class interval

So, we have:

Class 63-65:

M = \frac{1}{2}(63 + 65) = 64

Class 66 - 68:

M = \frac{1}{2}(66 + 68) = 67

When the computation is completed, the frequency distribution will be:

\begin{array}{ccc}{Midpoint} & {Class} & {Frequency} & {64} & {63-65} & {1}  & {67} & {66-68} & {11} & {70} & {69-71} & {8} &{73} & {72-74} & {7}  & {76} & {75-77} & {3} & {79} & {78-80} & {1}\ \end{array}

Solving (b): Mean and standard deviation using 1-VarStats

Using 1-VarStats, the solution is:

\bar x = 70.2903

\sigma = 3.5795

<em>See attachment for result of 1-VarStats</em>

8 0
3 years ago
80 - [50 - {20 ÷ 2 – (16 - 2÷ 2) ÷ 3}]
trapecia [35]

Answer:

35

Step-by-step explanation:

We have to solve the problems in the parenthesis first.

(16-2÷2)= (16-1)=(15)

20÷2-15÷3

(20÷2)-(15÷3)

10-5=5

50-5= 45

80-45= 35

Hope this helps!

6 0
3 years ago
I need help with this ​
djyliett [7]

Answer:I don't know this one.

Step-by-step explanation:

7 0
3 years ago
An unopened cereal box contains `15/28` cubic foot of cereal. If the box is full, and the length and height of the box are `5/7`
babymother [125]

Answer:

A. `1/2` foot

Step-by-step explanation:

The computation of the width of the box is shown below:

15 ÷ 28 = (5 ÷ 7)(1 1 ÷ 2)(width)

15 ÷ 28 = (5 ÷ 7)(3 ÷ 2)width

15 ÷ 28 = (15 ÷ 14)width

(15 ÷ 28) ÷ (15 ÷ 14) = width

(15 ÷ 28) × (14 ÷ 15) = width

w = 14 ÷ 28

= 1 ÷ 2 ft

7 0
3 years ago
Read 2 more answers
Other questions:
  • What does algebra mean?
    13·1 answer
  • (x2 + 17x + 63) divided (x +8)
    14·1 answer
  • Which is the place value of the 9 in the number 9,231,478?
    10·2 answers
  • Anton took out a 20-year loan for $90,000 at an APR of 10.5% compounded monthly, approximately what would be the total cost of h
    6·2 answers
  • Find the value of x in the triangle (not drawn to scale.)
    10·1 answer
  • What is 20 plus -14?
    11·2 answers
  • Find the diagonal of a square whose sides are of the given measure.<br><br> Given = 3√2
    6·1 answer
  • The diagram shows a triangle.<br><br> What is the value of b?
    10·1 answer
  • How can you find f(4) if f(x)=7x^(2)-5
    10·1 answer
  • Solve c2-4c3=25 by completing the square
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!