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3 years ago

What is the reciprocal of 2/7? A. - 3 1/2 B. - 2/7 C. 5/7 D. 3 1/2

1 answer:

4 0

The answer is B. The actual reciprocal is 7/2, since the answer means isn't there its means the reciprocal of the negative or positive sign

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2. Solve the system of equations. Write your answer in parametric vector notation. X, +5x2 + 4x3 + 3x4 +9xs = 18 2x, +6x2 + 4x3

ratelena [41]

Answer:

The system is inconsistent.

Step-by-step explanation:

The system is

$x_1+5x_2+4x_3+3x_4+9x_5=18\\2x_1+6x_2+4x_3+6x_4+6x_5=28\\3x_1+7x_2+4x_3+10x_4+x_5=41\\4x_1+6x_2+2x_3+7x_4+4x_5=29$

The associated matrix to the system is

$\left[\begin{array}{cccccc}1&5&4&3&9&18\\2&6&4&6&6&28\\3&7&4&10&1&41\\4&6&2&7&4&29\end{array}\right]$

Now we use row operations to find the echelon form of the matrix:

1. We substract to row 2, two times the row 1.

We substract to row 3, three times the row 1.

We substract to row 4, four times the row 1 and obtain the matrix

$\left[\begin{array}{cccccc}1&5&4&3&9&18\\0&-4&-4&0&-12&-8\\0&-8&-8&1&-26&-13\\0&-14&-14&-5&-32&-43\end{array}\right]$

2. We multiply the second row of the preview step by -1/4. We obtain the matrix

$\left[\begin{array}{cccccc}1&5&4&3&9&18\\0&1&1&0&3&2\\0&-8&-8&1&-26&-13\\0&-14&-14&-5&-32&-43\end{array}\right]$

We add to row 3, eight times the row 2.

We add to row 4, fourtheen times the row 2 and obtain the matrix

$\left[\begin{array}{cccccc}1&5&4&3&9&18\\0&1&1&0&3&2\\0&0&0&1&-2&3\\0&0&0&-5&10&-155\end{array}\right]$

4. We add to row 4 of the preview step, five times the row 3 and obtain the matrix

$\left[\begin{array}{cccccc}1&5&4&3&9&18\\0&1&1&0&3&2\\0&0&0&1&-2&3\\0&0&0&0&0&-140\end{array}\right]$

Using backward substitution we have that

$0x_5=-140$ , then $0=-140$ and this is absurd. Then The system is inconsistent.

4 0

4 years ago

Jackson's age was 2/5 of the age he will be 20 years from now 7 years ago. how old is jackson now

Dafna11 [192]

1 year old 5 divided by 20 times 2 minus 7

8 0

3 years ago

Please help ASAP!

Oliga [24]

The age of the students is about 0.67 years away from the 13.3 years.

The Mean Absolute Deviation is the average distance away from the mean. For the last choice, you should select more variable. Since the average is higher, there is a greater distance between the points and the mean.

3 0

3 years ago

Which of the following multiplication equations doesn't have the same solution as the others?

n200080 [17]

The answer is option 2: 4b = 7. The other options all equal 4.

3 0

3 years ago

Simplify: 21j-26+4j=21+6-2j

Molodets [167]

1. 21j-26+4j=21+6-2j
2. 25j-26=27-2j
3. 27j=53
4. j=53/27
hope this helps!!

3 0

3 years ago