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4 years ago

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Find a + b, 9a + 7b, |a|, and |a − b|. a = 9i − 8j + 7k, b = 7i − 9k

2 answers:

Evgesh-ka [11]4 years ago

7 0

A+b=9i-8j+7k+(7i-9k)
=9i-8j+7k+7i-9k
=16i-8j-2k
9a+7b=9(9i-8j+7k)+7(7i-9k)
=81i-72j+63k+49i-63k
=130i-72j
|a|=| 9i-8j+7k |
|a-b|=|9i-8j+7k-(7i-9k)|
=|9i-8j+7k-7i+9k|
=|2i-8j+16k|
i hope this is helping

Blababa [14]4 years ago

6 0

Answer:

Evaluations take place in the following manner.

Step-by-step explanation:

We are given the following information in the question:

$a = 9i-8j+7k\\b = 7i-9k$

We have to evaluate the following:

1) a+b

$a + b=16i - 8j-2k$

2) 9a+7b

$9a+7b = 9(9i-8j+7k)+7(7i-9k) \\=(81i-72j+63k)+(49i-63k)\\ = 130i-72j+126k$

3)|a|

$|a| = \sqrt{x^2 + y^2 + z^2}\\\text{where} ~a = xi + yj + zk\\\\|a| = \sqrt{81+64+49} = \sqrt{194} = 13.9283$

4) |a-b|

$a-b = (9i-8j+7k)-(7i-9k) = 2i-8j+16k\\\\|a-b| = \sqrt{2^2 + (-8)^2+(16)^2} = \sqrt{324} = 18$

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⇒ We have two points i.e,

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First calculate slope(m);

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Substitute the given values we get;

$m = \frac{40-25}{8-3}=\frac{15}{5}$ = 3

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Using distributive property; $a \cdot(b+c) = a\cdot b + a\cdot c$

$y-25 = 3x - 9$

Add 25 on both sides, we get;

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3 years ago

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vaieri [72.5K]

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3 years ago

rosa correctly solved 275 divided by 5.enter numbers in boxes to show the equations she could use to solve the problem

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