Algebra and Trig question. Please show work! Serious replies only! Thankyou so much!!?

Question

Solve by completing the square: x^2 -8x-4 =0

a). 4+- 2 square root 5
b). -2 +- 4 square root 5
c). -4 +- 2 square root 5
d). 2+- 5 square root 2

Answer 1

Completing the square

x² - 8x - 4 = 0

x² - 8x - 4 + 4 = 0 + 4

x² - 8x = 4

x² - 8x + _______= 4 + _____

x² - 8x + 16 = 4 + 16

(x - 4)(x + 4) = 20

(x - 4)² = 20

(√x - 4)² = ± √20

x - 4 = ± √20

x - 4 = ± √4√5

x - 4 = ± 2 √5

x - 4 + 4 = 4 ± 2 √5

x = 4 ± 2√5. . .This is your answer

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I will take it a step further

x = 4 ± 2√5

x = 4 ± 2(2.236067978)

x = 4 ± 4.72135955

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Solving for +

x = 4 + 4.472135955

X = 8.472135955

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Solving for -

x = 4 - 4.72135955

x = - 0.472135955

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The orther steps is the roots or solution for completing the square

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Answer 2

1) Move the number to the right side of the equation:
x^2 - 8x = 4

2) Add a term to both sides that makes the left side into a perfect square. The easiest way to do this is to take the coefficient of the x term (8), divide it by 2 (8/2 = 4) and square it (4^2 = 16). Therefore, you should add 16 to both sides.
x^2 - 8x + 16 = 4 + 16

3) Factor the perfect square.
(x - 4)^2 = 20

4) Solve for x.
x - 4 = +/- square root 20
x = 4 +/- square root 20

The square root of 20 simplifies into 2 square root 5. Therefore, the answer is A.

Answer 3

x^2 -8x-4 =0
x^2 - 8x = 4
x^2 - 8x + 16 = 4 + 16
(x - 4)^2 = 20
x - 4 = +/- sqrt(20)

x - 4 = sqrt(20) -> x = sqrt(20) + 4 -> 2 sqrt(5) + 4
x - 4 = - sqrt(20)-> x = -sqrt(20) +4 -> -2sqrt(5) + 4

the answer is A

When are you going to learn how to do this yourself?

Answer 4

let x be the "different" attitude. Then the first attitude should be 2x-15. Complementary angles upload as a lot as ninety ranges. So the equation reads x + (2x-15) = ninety. Simplify, 3x-15 = ninety. upload 15 to both area, 3x = one 0 5. Divide both area by technique of three, x = 35. it really is the smaller attitude. the first attitude is 2x35-15, that's 55 ranges. it really is the better attitude, so "c" is the answer.

Answer 5

(x-4)^2 = 20
so (a)