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11Alexandr11 [23.1K]
3 years ago
9

Solve: x2 + 8x - 9 = 0 please i need it urgently​

Mathematics
1 answer:
Likurg_2 [28]3 years ago
6 0

Answer:

x = 1 or x = -9

Step-by-step explanation:

Solve for x over the real numbers:

x^2 + 8 x - 9 = 0

Hint: | Solve the quadratic equation by completing the square.

Add 9 to both sides:

x^2 + 8 x = 9

Hint: | Take one half of the coefficient of x and square it, then add it to both sides.

Add 16 to both sides:

x^2 + 8 x + 16 = 25

Hint: | Factor the left hand side.

Write the left hand side as a square:

(x + 4)^2 = 25

Hint: | Eliminate the exponent on the left hand side.

Take the square root of both sides:

x + 4 = 5 or x + 4 = -5

Hint: | Look at the first equation: Solve for x.

Subtract 4 from both sides:

x = 1 or x + 4 = -5

Hint: | Look at the second equation: Solve for x.

Subtract 4 from both sides:

Answer: x = 1 or x = -9

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Write the percentage below as a decimal. 15%
Nadya [2.5K]

Answer: 0.15.

Step-by-step explanation:This is the same as moving the decimal point two places to the left. For example, 15% is equivalent to the decimal 0.15. Notice that dividing by 100 moves the decimal point two places to the left.

6 0
4 years ago
Help me please!!!!!!!
user100 [1]

ignore this my answer was wrong . Sorry


5 0
3 years ago
Mr. Zillow wants to research the prices in a Subdivision near Disney World called World of Homes. The prices of 14 homes in this
ExtremeBDS [4]

Answer:

Looking for four values or answers

(A) 5.05

(B) 13

(C) $254,140.33

(D) $254,145.38

Step-by-step explanation:

(A) The value of the margin of error.

Using a 90% confidence level or 0.10 alpha level,

1 - alpha = 1 - 0.10 = 0.90

The degrees of freedom = n - 1 = 14 - 1 = 13

Using the t table, 0.90 under 13 is 1.350

Sample size divided by √n is equal to

14/√14 = 3.742

1.35 × 3.742 = 5.05

(B) 13 degrees of freedom

(C) To find the lower and upper limits, you find the mean value first and then subtract / add to half of the margin of error which is 5.05÷2 = 2.525

Adding the 14 values together, you have $3,558,000

Dividing by 14 to get the mean;

Mean = $254,142.8571

Lower Limit: $254,140.33

Upper Limit: $254,145.38

4 0
3 years ago
How high is the poster?
Mila [183]

Answer:

24

Step-by-step explanation:

12 x 2

7 0
3 years ago
Read 2 more answers
Use the area of a rectangle and the Distributive<br> Property to find each product.<br> 9 X 34
OLga [1]

Answer:

Step-by-step explanation:

Write 34 in tens and units.

34 = 30 + 4

9(30 + 4)

9 * 30 = 270

9* 4 = 36

270 + 36 = 306

After awhile if your practice enough, you can do them in your head.

5 0
3 years ago
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