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3 years ago

Find a 33 matrix Sij so that the product SijA is the same as the matrix A after applying the row operation Ri $ Rj .

Mathematics

1 answer:

aleksklad [387]3 years ago

6 0

Answer:

We want the ith row of the new matrix SijA to be the old jth row of A, so we need the ith row of Sij to extract the jth entry of column of A.

This mean the ith row of Sij must have a 1 in the jth entry and 0's everywhere else.

Similarly, the jth row of Sij must have a 1 in the ith entry and 0's everywhere else.

in the piecewise notation this is

(Sij)kl ={1 if k=i and l=j, 1 if k=k and l=i; 1 if k=l but k#i,j, 0 otherwise

Step-by-step explanation:

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Best answer gets brainiest. Mackenzie went to the mall with her mom. First, they spent 15 minutes in the shoe store. Then they s

Naddika [18.5K]

Answer:

They started at 4:45 pm

Step-by-step explanation:

Time spend at the mall:

15 minutes in the shoe store

1 hour shopping for a dress

30 minutes eating

Total 1 hour 45 minutes

x + 1 hour 45 minutes = 6:30

Subtract 1 hours

5 : 30 pm

Subtract 45 minutes

4 :45 pm

They started at 4:45 pm

8 0

2 years ago

Julio started biking to the park traveling 8 mph, after some time the bike got a flat so Julio walked the rest of the way, trave

USPshnik [31]

Answer:

Julio travel 3 hours by biking and 4 hours by walking.

Step-by-step explanation:

Given:

Julio started biking to the park traveling 8 mph, after some time the bike got a flat so Julio walked the rest of the way, traveling 7 mph.

If the total trip to the park took 7 hours and it was 52 miles away.

Now, to find the time Julio travel at each speed.

The speed travelled by the bike = 8 mph.

The speed travelled by the walking = 7 mph.

Let the time Julio travel with bike be $x.$

And the time Julio travel by walking be $y.$

As, given Julio started biking to the park traveling, after some time the bike got a flat so Julio walked the rest of the way,

Thus, the total time taken:

$x+y=7$

$y=7-x\ \ \ .......(1)$

So, the distance travelled by bike:

Speed × time

$8\times x=8x$

And, the distance travelled by walking:

Speed × time

$7\times y=7y$

Now, the total distance travelled by Julio:

$8x+7y=52$

Substituting the value of $x$ from equation (1) we get:

$8x+7(7-x)=52$

$8x+49-7x=52\\\\x+49=52$

Subtracting both sides by 49 we get:

$x=3.$

The time Julio travelled with bike = 3 hours.

Now, to get the time Julio travelled by walking by substituting the value of $x$ :

$y=7-x\\\\y=7-3\\\\y=4\ hours.$

The time Julio travelled by walking = 4 hours.

Therefore, Julio travel 3 hours by biking and 4 hours by walking.

7 0

3 years ago

I will mark brainliest ,thank, and rate to to the best answer!Please help! ASAP

Over [174]

Answer:

1st, 3rd, and 6th

Step-by-step explanation:

Let's look at each statment...

1.) Correct

Explanation: 10 percent of the students at the school participate in soccer. If 140 is 10% of the number of students at the school, there is more than 140 students at this school.

2.) Incorrect

Explanation: We've already established that the # of students at the school is more than 140.

3.) Correct

Explanation: 10% as a decimal is 0.1 Divide 140 by 0.1 and you get 1,400. So, the total number of students is 1,400.

4.) Incorrect

Explanation: We've already established that the number of students is 1,400, not 290.

5.) Incorrect

Explanation: We've already established that the number of students is 1,400, not 150.

6.) Incorrect

Explanation: If the percent was a ratio, it would be 10:100 or 10/100. This is because a whole percent is 100% and the percent of students who play soccer is 10%.

7.) Correct

Explanation: We've already established that the ratio would be 10:100 or 10/100. Thus, this is correct.

I hope this helps! :)

3 0

2 years ago

Read 2 more answers

Use the distributive property to remove the parentheses.

kifflom [539]

Answer:

10x + 8y - 2

Step-by-step explanation:

$-2(-5x – 4y+1) \\ \\ = ( - 2)( - 5x) - 2 ( - 4y) - 2 \times 1 \\ \\ = 10x + 8y - 2$