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nasty-shy [4]
3 years ago
15

Translate the following verbal expression into an algebraic expression.

Mathematics
1 answer:
poizon [28]3 years ago
5 0

Answer:

3 * (x + 7)

Step-by-step explanation:

Mark number as x

Then the sum of a number and seven is x + 7

Three times x + 7 can be written as

3 * (x + 7)

Parentheses mean that we first add x and 7 and then multiply their sum by 3

Alternatively you can write it as 3x + 21, since

3 * (x + 7) = 3 * x + 3 * 7 = 3x + 21

You might be interested in
(a) By inspection, find a particular solution of y'' + 2y = 14. yp(x) = (b) By inspection, find a particular solution of y'' + 2
SOVA2 [1]

Answer:

(a) The particular solution, y_p is 7

(b) y_p is -4x

(c) y_p is -4x + 7

(d) y_p is 8x + (7/2)

Step-by-step explanation:

To find a particular solution to a differential equation by inspection - is to assume a trial function that looks like the nonhomogeneous part of the differential equation.

(a) Given y'' + 2y = 14.

Because the nonhomogeneus part of the differential equation, 14 is a constant, our trial function will be a constant too.

Let A be our trial function:

We need our trial differential equation y''_p + 2y_p = 14

Now, we differentiate y_p = A twice, to obtain y'_p and y''_p that will be substituted into the differential equation.

y'_p = 0

y''_p = 0

Substitution into the trial differential equation, we have.

0 + 2A = 14

A = 6/2 = 7

Therefore, the particular solution, y_p = A is 7

(b) y'' + 2y = −8x

Let y_p = Ax + B

y'_p = A

y''_p = 0

0 + 2(Ax + B) = -8x

2Ax + 2B = -8x

By inspection,

2B = 0 => B = 0

2A = -8 => A = -8/2 = -4

The particular solution y_p = Ax + B

is -4x

(c) y'' + 2y = −8x + 14

Let y_p = Ax + B

y'_p = A

y''_p = 0

0 + 2(Ax + B) = -8x + 14

2Ax + 2B = -8x + 14

By inspection,

2B = 14 => B = 14/2 = 7

2A = -8 => A = -8/2 = -4

The particular solution y_p = Ax + B

is -4x + 7

(d) Find a particular solution of y'' + 2y = 16x + 7

Let y_p = Ax + B

y'_p = A

y''_p = 0

0 + 2(Ax + B) = 16x + 7

2Ax + 2B = 16x + 7

By inspection,

2B = 7 => B = 7/2

2A = 16 => A = 16/2 = 8

The particular solution y_p = Ax + B

is 8x + (7/2)

8 0
3 years ago
The average household income for a recent year was $30,000. five years earlier the average household income was $24,500. assume
ikadub [295]

Using hypothesis test, we conclude that there is evidence to believe that the average household income has increased.

According to the question,

The average household income for a recent year (x₁⁻) = $30,000

The average household income for a recent year (x₂⁻) = $24,500

sample sizes n₁ = n₂ = 34

standard deviation of both samples were $24,500. Thus, s₁ = s₂ = $5928.

Null hypothesis:  There is no evidence to believe that the average household income has increased.

H₀ : μ₁ ≤ μ₂

Alternative hypothesis:  There is evidence to believe that the average household income has increased.

H₁: μ₁ > μ₂  

To check hypothesis we have the formula

Standard error=  \sqrt{\frac{s_{1} ^{2} }{n_{1} } + \frac{s^{2} _{2} }{n_{2} }  }

= \sqrt{2067128.4706}

= 1437.7512

Thus, standard error is $1437.7512.

Formula for test statistic = [(x₁⁻ -  x₂⁻) - (μ₁ - μ₂)]/standard error

= [(30000 -  24500) - 0]/1437.7512

= 3.8254

The critical value of z at 5% level of significance is 1.6449.

Here, the calculated value is greater than the critical value so we reject H₀.

Hence using hypothesis test, we conclude that there is evidence to believe that the average household income has increased.

Learn more about hypothesis test here

brainly.com/question/15060525

#SPJ2

3 0
2 years ago
Please help picture below
Strike441 [17]
The answer is 5 and 0

(-5) + 5 = 0
4 0
2 years ago
How do you find the intersection of two sets?
Vlad [161]
To find the intersection<span> of these </span>two sets<span>, we need to find out what elements they have in common. The numbers 3, 4, 5 are elements of both </span>sets, therefore theintersections<span> of A and B is {3. 4. 5].</span>
3 0
3 years ago
PLEASE ANsWer THiS<br> Question in picture ⬇️<br><br> There are two
olasank [31]

Answer:

dude you have complicated questions

Step-by-step explanation:

6 0
3 years ago
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