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Andreyy89
3 years ago
11

Factor by completing the square 5x^2-21=10x

Mathematics
1 answer:
velikii [3]3 years ago
4 0
Solve for x over the real numbers:
5 x^2 - 21 = 10 x

Subtract 10 x from both sides:
5 x^2 - 10 x - 21 = 0

Divide both sides by 5:
x^2 - 2 x - 21/5 = 0

Add 21/5 to both sides:
x^2 - 2 x = 21/5

Add 1 to both sides:
x^2 - 2 x + 1 = 26/5

Write the left hand side as a square:
(x - 1)^2 = 26/5

Take the square root of both sides:
x - 1 = sqrt(26/5) or x - 1 = -sqrt(26/5)

Add 1 to both sides:
x = 1 + sqrt(26/5) or x - 1 = -sqrt(26/5)

Add 1 to both sides:
Answer:  x = 1 + sqrt(26/5) or x = 1 - sqrt(26/5)
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(x+8)^2 = 256+x^2

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2 years ago
What is the mode and median of 1,2,1,3,3,5,3,4,5,4,3,2,5,3,1.​
tankabanditka [31]

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8 0
3 years ago
Which of the following represents the total cost of the shoes by applying the $15 coupon first and the 20% member discount secon
murzikaleks [220]

Considering the definition of an equation and the way to solve it, the total cost of the shoes is 0.20×(x-15).

<h3>Definition of equation</h3>

An equation is the equality existing between two algebraic expressions connected through the equals sign in which one or more unknown values, called unknowns, appear in addition to certain known data.

The members of an equation are each of the expressions that appear on both sides of the equal sign while the terms of an equation are the addends that form the members of an equation.

<h3>Total cost in this case</h3>

Being "x" the price of the shoes, and knowing that:

  • you apply a discount of $15 first → x -15
  • you apply a discount of 20% through a second discount (
  • (applied on the first discount already made) → 20%×(x-15) → 0.20×(x-15)

the equation in this case is:

<u><em>Total cost= 0.20×(x-15)</em></u>

Finally, the total cost of the shoes is 0.20×(x-15).

Learn more about equations:

brainly.com/question/4983716

brainly.com/question/13314678

#SPJ1

8 0
1 year ago
A culture of 1.08×1015 bacteria is in petri dish A. A culture of 2.7×1011 bacteria is in petri dish B. How many times greater is
xxTIMURxx [149]
<span>Culture in petri dish A is 1.08 x 10^15 and culture in petri dish B is 2.7 X 10^11. To determine how much greater petri dish A is from petri dish b, you must divide petri dish A by petri dish b. When you divide the two numbers, the answer is 4,000. The number of bacteria in petri dish A is four thousand times greater than the number of bacteria in petri dish B.</span>
4 0
3 years ago
Read 2 more answers
I don't really understand this, please help. Also, if you could show how you got your answer, that would help.
Varvara68 [4.7K]
What is 20% of 100? It would be 20! so 120
120-30%=84. 
a. 84 pumpkins were left.
b. The final number of pumpkins were less than Brianna had hoped for.

hope this helps! :)
3 0
3 years ago
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