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jolli1 [7]
4 years ago
13

Use quadratic formula solve .7x^2 - 28x - 7​

Mathematics
1 answer:
beks73 [17]4 years ago
6 0

Answer:

x = 2 + sqrt(5) or x = 2 - sqrt(5)

Step-by-step explanation using the quadratic formula:

Solve for x over the real numbers:

7 (x^2 - 4 x - 1) = 0

Divide both sides by 7:

x^2 - 4 x - 1 = 0

Add 1 to both sides:

x^2 - 4 x = 1

Add 4 to both sides:

x^2 - 4 x + 4 = 5

Write the left hand side as a square:

(x - 2)^2 = 5

Take the square root of both sides:

x - 2 = sqrt(5) or x - 2 = -sqrt(5)

Add 2 to both sides:

x = 2 + sqrt(5) or x - 2 = -sqrt(5)

Add 2 to both sides:

Answer:  x = 2 + sqrt(5) or x = 2 - sqrt(5)

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What is the radius of the circle who’s equation is x^2 + y^2 = 9
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Answer:

r=3

Step-by-step explanation:

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How to find cube root without find the prime factors​
dsp73

Answer:

Below.

Step-by-step explanation:

One method is by Trial and Improvement.

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We know that cube root of 8 is 2 and cube root of 27 is 3 so the cube root of 20 is between 2 and 3.

So we could try 2.5:

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So we need to go higher so we try 2.6*3:

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This is a rather long process.......

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