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4 years ago

Solve for x in the equation 2x^2-4x-9=29

Mathematics

1 answer:

Andrews [41]4 years ago

3 0

Answer:

x = 1 ±2sqrt(5)

Step-by-step explanation:

2x^2-4x-9=29

Add 9 to each each side

2x^2-4x-9+9=29+9

2x^2-4x=38

Divide by 2

2/2x^2-4/2x=38/8

x^2 -2x =19

Complete the square

x^2 -2x + (-2/2)^2 = 19 +(-2/2)^2

x^2 -2x +1 = 19+1

(x-1)^1=2 = 20

Take the square root of each side

sqrt((x-1)^2) = ±sqrt(20)

x-1 = ±sqrt(20)

Add 1 to each side

x-1+1 = 1 ±sqrt(20)

x = 1 ±sqrt(20)

Simplifying the square root of 20

x = 1 ±sqrt(4)sqrt(5)

x = 1 ±2sqrt(5)

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Using pythagorean therom whats the answer ?? a2 + b2 = c2

swat32

By using Pythagorean Theorem,
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Hope it helps!

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3 years ago

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Step-by-step explanation:

Rule:

When exponents multiply, they're adding.

Multiply:

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2 years ago

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Contact [7]

Answer: a. n= 1068

b. n= 164

Step-by-step explanation:

The formula to find the sample size :

$n=p(1-p)(\dfrac{z^{*}}{E})^2$

, where p=prior population proportion , z* = critical z-value and E = Margin of error.

Here , let p=proportion of computers that use a new operating system.

Given : Confidence level = 95%

i.e. z* = 1.96 [by z-table]

Margin of error : E = 3% =0.03

a. If p is unknown , then we assume p=0.5

Then, $n=(0.5)(1-0.5)(\dfrac{1.96}{0.03})^2=1067.11111\approx1068$

i.e. n= 1068

b. p=0.96

Then, $n=(0.96)(1-0.96)(\dfrac{1.96}{0.03})^2=163.908266667\approx164$

i.e. n= 164.

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GuDViN [60]

Answer:

Step-by-step explanation:

the number in the middle

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