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3 years ago

Complex numbers x^2-4x-21=0

Mathematics

1 answer:

kolezko [41]3 years ago

5 0

Answer:

x = -3, 7

Step-by-step explanation:

x² - 4x - 21 = 0

factor (what multiplies to -21 and adds to -4?):

3 and -7

(x + 3)(x - 7) = 0

zero product property:

x = -3, 7

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Write the product in standard form (2x + 5) ^2

Iteru [2.4K]

Answer:

4x^2+20x+25

Step-by-step explanation:

(2x+5)^2 = (2x+5) (2x+5)

Using the foil method : 2x(2x) = 4x^2

(2x) (5) = 10x

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3 years ago

The point(5/13,Y) IS IN THE 4TH quadrant corresponds to angle on the unit circle

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4th quadrant is positive x (cos) and negative y (sin)

Use the Pythagorean Theorem to calculate the value of y (sin).
x² + y² = c²
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25 + y² = 169
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Since the y-value is negative in the 4th quadrant, then y = -12

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3 years ago

Suppose the average yearly salary of an individual whose final degree is a master's is $41 thousand less than twice that of an

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Answer:

The average salary of master's degree people is $ 63,000 And

The average salary of bachelor's degree people is $ 52,000

Step-by-step explanation:

Given in question as :

Let the average salary of master's degree people = $ M And

Let the average salary of bachelor's degree people = $ B

According to question ,

The average salary of master's degree people + The average salary of bachelor's degree people = $115,000

Or , $ M + $ B = $ 115,000 ............. A

Again ,

$ M = 2 × $ B - $ 41,000 ............... B

From eq A and eq B

(2 × $ B - $ 41,000 ) + ( $ B ) = $ 115,000

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And M = $ 115,000 - $ 52,000

∴ M = $ 63,000

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The average salary of bachelor's degree people is $ 52,000 Answer

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3 years ago

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I think the second one hope this helps

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3 years ago

there is a beaker of 3.5% acid solution and a beaker of 6% acid solution in the science lab. Mr. Larson needs 200ml of 4.5% acid

disa [49]

Below are the choices:

A. 80 mL of the 3.5% solution and 120 mL of the 6% solution

B. 120 mL of the 3.5% solution and 80 mL of the 6% solution 

C. 140 mL of the 3.5% solution and 60 mL of the 6% solution 

D. 120 mL of the 3.5% solution and 80 mL of the 6% solution

Let fraction of 3.5% in final solution be p.

p * 3.5 + (1 - p) * 6 = 4.5 

3.5p + 6 - 6p = 4.5 

2.5p = 1.5 

p = 3/5 

3/5 * 200 = 120 

Therefore the answer is B. 120 ml of 3.5% and 80 ml of 6%.

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3 years ago

Complex numbers x^2-4x-21=0​

Complex numbers x^2-4x-21=0