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2 years ago

Find the solutions to the quadratic equation below by completing the square. x2 - 8x - 7 = 0

Mathematics

1 answer:

Furkat [3]2 years ago

3 0

Answer:

x=4- $\sqrt{23}$ , x=4+ $\sqrt{23}$

Step-by-step explanation:

(x^2-8x+16)-16-7=0

(x-4)^2=23

x=4- $\sqrt{23}$ , x=4+ $\sqrt{23}$

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Find the mean, median, and mode for 0, 4, 6, 11, 9, 8, 9, 1, 5, 9, 7. Round to the nearest tenth if needed.

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3 years ago

Adalyn earns $42 for mowing lawns for 6 hours. If Adalyn charges at the same rate, how many hours will it takes her to earn $63

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How do you solve -2(3x-1)-3=4x+5-x

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-6x+2-3=3x+5

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3 years ago

Suppose a flare is shot from the top of a 120 foot building at a speed of 160 feet per second. The equation h = ?16t + 160t + 12

insens350 [35]

Answer:

The time taken for the flare to hit the ground is approximately 10.7 seconds.

Step-by-step explanation:

Given : Suppose a flare is shot from the top of a 120 foot building at a speed of 160 feet per second. The equation $h =- 16t^2+ 160t + 120$ models the h height at t seconds of the flare.

To find : How long will it take for the flare to hit the ground?

Solution :

The equation $h =- 16t^2+ 160t + 120$ models the h height at t seconds of the flare.

The flare to hit the ground when h=0.

Substitute in the equation,

$-16t^2+ 160t + 120=0$

Applying quadratic formula, $x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

Where, a=-16, b=160 and c=120

$x=\frac{-160\pm\sqrt{160^2-4(-16)(120)}}{2(-16)}$

$x=\frac{-160\pm\sqrt{33280}}{-32}$

$x=\frac{-160\pm 182.42}{-32}$

$x=\frac{-160+182.42}{-32},\frac{-160-182.42}{-32}$

$x=−0.70,10.70$

Reject the negative value.

Therefore, the time taken for the flare to hit the ground is approximately 10.7 seconds.

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2 years ago

What is the solution to the inequality below x2>25

4vir4ik [10]

Answer:

Ans: (-5, 5)

-5 < x < 5

Step-by-step explanation:

Standard form: f(x) = x^2 - 25 < 0.

First solve x^2 - 25 = 0 --> x = +- 5

Use the algebraic method to solve f(x) < 0. Between the 2 real roots (-5) and (5), f(x) < 0, as opposite in sign to a = 1.

Answer by open interval: (-5, 5)

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