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1 year ago

Solve x2 + 6x = 7 by completing the square. Which is the solution set of the equation?

Mathematics

2 answers:

Doss [256]1 year ago

8 0

Answer:

x = 1; x = -7

Step-by-step explanation:

Given

x^2 + 6x = 7

we want to complete the square. If we have (x + a)^2 and expand it we get: x^2 + 2ax + a^2. The second term in the equation suggest that 2ax = 6x or a = 3. Then, adding 3^2 at both sides of the equation of the problem:

x^2 + 6x + 3^2 = 7 + 3^2

(x + 3)^2 = 16

x + 3 = sqrt(16)

That gives us two options

x + 3 = 4

x = 1

x + 3 = -4

x = -7

Ber [7]1 year ago

7 0

So first you have to find the perfect square that matches up with x^2 + 6x

so half of 6, and square it. your perfect square is 9

x^2 + 6x + 9 = 7 + 9

then, condense the left side of the equation into a squared binomial:

(x + 3)^2 = 16

take the square root of both sides:

x + 3 = ± √16

therefore:

x + 3 = ± 4

x = - 3 ± 4

so your solution set is:

x = 1, -7

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Yuson must complete 210 min of community service. She does 30 min each day. Which linear equation represents the number of minut

Misha Larkins [42]

Answer:

$y=-30x+210$

Step-by-step explanation:

Let

x -----> the number of days

y ----> the number of minutes Yuson has left

we know that

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$y=mx+b$

where

m is the slope

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In this problem we have

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substitute the values

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2 years ago

A company wants to establish that the mean life of its batteries, when used in a wireless mouse, is over 183 days. The data will

enyata [817]

Answer:

a) Null and alternative hypotheses are:

$H_{0}$ : mu=183 days

$H_{a}$ : mu>183 days

b) If the true mean is 190 days, Type II error can be made.

Step-by-step explanation:

Let mu be the mean life of the batteries of the company when it is used in a wireless mouse

Null and alternative hypotheses are:

$H_{0}$ : mu=183 days

$H_{a}$ : mu>183 days

Type II error happens if we fail to reject the null hypothesis, when actually the alternative hypothesis is true.

That is if we conclude that mean life of the batteries of the company when it is used in a wireless mouse is at most 183 days, but actually mean life is 190 hours, we make a Type II error.

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2 years ago

D(-3+x)=kx+9 solve for x

Gnesinka [82]

d(-3 + x) = kx + 9