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3 years ago

Does anyone know why x is normally used for an unknown number?

Mathematics

1 answer:

jeka943 years ago

7 0

Then you are able to substitute in X and it can have a infinite number of values catered to the question.

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Help, please Ill mark brainliest!

aev [14]

Answer:

the answers are 12.5, 5, 2, 0.8 and 0.32

Step-by-step explanation:

2(0.4)^-2

=2(6.25)

= 12.5

2(0.4)^-1

= 2(2.5)

2(0.4)^0

=2(1)

2(0.4)^1

=2(0.4)

=0.8

2(0.4)^2

=2(0.16)

=0.32

4 0

2 years ago

What is the measurement of the missing angle?

RSB [31]

Answer:

Step-by-step explanation:

180-40+20=120

180-120+39=?

99=?

6 0

3 years ago

What is<br> is 1/4 + 9/10y -3/5y +7/8 written in simplest form?

Leviafan [203]

Answer:

Step-by-step explanation:

$\frac{1}{4}+\frac{9}{10}y - \frac{3}{5}y+\frac{7}{8}\\\\=\frac{1}{4}+\frac{7}{8}+\frac{9}{10}y-\frac{3}{5}y\\\\$

Combine like terms. 1/4 and 7/8 are like terms and LCD of 4 and 8 is 8

9/10y and -3/5y are like terms and LCD of 10 , 5 is 10

$= \frac{1*2}{4*2}+\frac{7}{8}+\frac{9}{10}y-\frac{3*2}{5*2}y\\\\=\frac{2}{8}+\frac{7}{8}+\frac{9}{10}y-\frac{6}{10}y\\\\=\frac{9}{8}+\frac{3}{10}y$

5 0

2 years ago

Read 2 more answers

Evaluate plzzz help am giving brainliest

Lapatulllka [165]

Answer:2

Step-by-step explanation:

6 0

2 years ago

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.<br> Evaluate the series 1 + 0.1 + 0.01 + . . .

EastWind [94]

We can employ a simple repeated decimal trick:

$x=1.111\ldots$

$0.1x=0.111\ldots$

$\implies x-0.1x=1\implies0.9x=1\implies x=\dfrac1{0.9}=\dfrac{10}9$

###

Alternatively, we can compute the partial sum of the series.

$\displaystyle S_n=\sum_{k=0}^n\dfrac1{10^k}$

$S_n=1+0.1+0.01+\cdots+\dfrac1{10^n}$

$0.1S_n=0.1+0.01+0.001+\cdots+\dfrac1{10^{n+1}}$

$\implies S_n-0.1S_n=0.9S_n=1-\dfrac1{10^{n+1}}$

$\implies S_n=\dfrac{10}9-\dfrac9{10^n}$

As $n\to\infty$ , the second term vanishes and we're left with $\dfrac{10}9$ . Notice that this is really just a more formal version of the earlier trick.

6 0

2 years ago

Read 2 more answers