3 years ago

Evaluate the expressuon 7-2(x-4) when x=5

Mathematics

2 answers:

givi [52]3 years ago

5 0

7 - 2(x - 4)...when x = 5
7 - 2(5 - 4) =
7 - 2(1) =
7 - 2 =
5 <==

expeople1 [14]3 years ago

3 0

It's 5 because 7-2(1).

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Find the area of a circle with radius, r = 1cm. Give your answer in terms of π .

natulia [17]

Answer:

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Step-by-step explanation:

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3 years ago

Cos(-170°) = _____<br><br> -cos10°<br> cos10°<br> cos(-10°)

ikadub [295]

<em>The right answer for:</em>

<h2>Explanation:</h2>

The cosine function is an even function, which means that for every point $(x,y)$ on the graph of $y=cos(x)$ then the point $(-x,y)$ also lies on the graph of the function. In other words, we can write:

$cos(-170^{\circ})=cos(170^{\circ})$

But:

$170^{\circ}=180^{\circ}-10^{\circ}$

So:

$cos(170^{\circ})=cos(180^{\circ}-10^{\circ})$

By property:

$cos(a-b)=cosacosb+sinasinb \\ \\ a=180^{\circ} \\ \\ b=10^{\circ} \\ \\ cos(170^{\circ} )=cos(180^{\circ} -10^{\circ})=cos180^{\circ} cos10^{\circ} +sin180^{\circ} sin10^{\circ} \\ \\ cos(170^{\circ})=-cos(10^{\circ})+0 \\ \\ \boxed{cos(170^{\circ})=-cos(10^{\circ})}$