Will give brainliest answer What is the value of a21? A.36 B. 58 C.60 D. 41

Mathematics

1 answer:

Strike441 [17]4 years ago

7 0

Answer:

Step-by-step explanation:

Matrix Multiplication follows a row-column format. In order to compute this, you must be familiar with vector dot products.

With that in mind, lets get straight into it.

The order that matrix multiplication follows means that the terms in the result are filled in left to right, then top to bottom.

Therefore, a21 will be the 3 value that is computed. This is important becuase this allows to directly compute a21, instead of using up a lot of time computing all the values before.

As a21 is located in the bottom row 1st column, we take the dot product of the 2nd row in matrix 1 and the 1 column in matrix two.

So we have:

(7 2) dot (5 3) = 7*5 + 2*3 = 41

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Two swimmers at opposite ends of a ninety-foot pool start to swim the length of the pool, one at 3 feet per second and the other

Mashutka [201]

Answer:

20 times

Step-by-step explanation:

The faster swimmer can swim twice the length of the pool in ...

(2·90 ft)/(3 ft/s) = 60 s

The slower swimmer can do it in ...

(2·90 ft)/(2 ft/s) = 90 s

The least common multiple of these times is 180 s = 3 minutes, after which time each swimmer will be back where they started.

A graph of position vs. time shows the swimmers pass 5 times in that 3-minute period. 4 of those are passes when they are going in opposite directions. A 5th pass occurs at one end of the pool, when the faster swimmer passes the slower one going in the same direction.

Since there are 5 passes in each 3-minute period, there are 20 passes in 12 minutes.

The swimmers pass each other 20 times in 12 minutes.