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2 years ago

6

If the line passing through the points (a, 1) and (−17, 8) is parallel to the line passing through the points (0, 5) and (a + 2,

1), what is the value of a?

1 answer:

stellarik [79]2 years ago

4 0

Parallel line means the same slope
（8-1）/(-17-a)=(1-5)/(a+2)
so a is 18

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Answer:

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Step-by-step explanation:

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Allan drew a polygon with 4 sides and 4 angles. All four sides are equal. None of the angles are right angles. What figure did A

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Answer: The figure drawn by Alan is a rhombus.

Step-by-step explanation:

Given: Allan drew a polygon with 4 sides and 4 angles with two properties:-

All four sides are equal.
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2 years ago

The half-life of a radioactive element is 130 days, but your sample will not be useful to you after 80% of the radioactive nu

gtnhenbr [62]

Answer:

We can use the sample about 42 days.

Step-by-step explanation:

Decay Equation:

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Integrating both sides

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$\therefore ln|N|=-\lambda t+ln|N_0|$

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$ln|\frac mn|= ln|m|-ln|n|$
$ln|ab|=ln|a|+ln|b|$

$ln|e^a|=a$

$ln|a|=b \Rightarrow a=e^b$
$ln|1|=0$

130 days is the half-life of the given radioactive element.

For half life,

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$\rightarrow ln|1|-ln|2|-ln|1|=-\lambda \times 130$

$\rightarrow -ln|2|=-\lambda \times 130$

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$\rightarrow \lambda= \frac{ln|2|}{130}$

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$\Rightarrow ln|{{\frac {80}{100}|=-\frac{ln2}{130}t$

$\Rightarrow ln|{{ {80}|-ln|{100}|=-\frac{ln2}{130}t$

$\Rightarrow t=\frac{ln|80|-ln|100|}{-\frac{ln|2|}{130}}$

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We can use the sample about 42 days.

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