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2 years ago

Solve the following system of equations. Show your work -3-3y=12x , -5-y=2x

Mathematics

1 answer:

tekilochka [14]2 years ago

4 0

solving simultaneously

let equation 1 be -3-3y=12x

let equation 2 be -5-y=2x

equation 2 make y subject of formula=> y=-5-2x

replace (y=-5-2x) in equation 1

-3-3(-5-2x)=12x

solve for x

x=2

replace x=2 in equation 2

y=-5-2(2)

y=-9

Therefore, x=2 y=-9

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Multiply 3x by -6, it gives you -18 so I'm going to say D

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3 years ago

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Divide 56 in a ratio of 5.3

Varvara68 [4.7K]

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3 years ago

A leprechaun places a magic penny under a girls pillow. The next night there are 2 magic pennies under her pillow. The following

kiruha [24]

Answer:

After 47 days she will have more than 90 trillion pennies.

Step-by-step explanation:

At the beginning there was 1 penny. At the second day the amount of pennies under the pillow became 2.

The amount of pennies doubled each day. So the series is,

$1,2,4,8,16,32,.....$

This series is in geometric progression.

As the pennies from each of the previous days are not being stored away until more pennies magically appear so the sum of series will be,

$S_n=\dfrac{a(r^n-1)}{r-1}$

where,

a = initial term = 1,

r = common ratio = 2,

As we have find the number of days that would elapse before she has a total of more than 90 trillion, so

$\Rightarrow 90\times 10^{12}\le \dfrac{1(2^n-1)}{2-1}$

$\Rightarrow 90\times 10^{12}\le \dfrac{2^n-1}{1}$

$\Rightarrow 90\times 10^{12}\le 2^n-1$

$\Rightarrow 2^n\ge 90\times 10^{12}+1$

$\Rightarrow \log 2^n\ge \log (90\times 10^{12}+1)$

$\Rightarrow n\times \log 2\ge \log (90\times 10^{12}+1)$

$\Rightarrow n \ge \dfrac{\log (90\times 10^{12}+1)}{\log 2}$

$\Rightarrow n \ge 46.4$

$\Rightarrow n\approx 47$

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2 years ago

From deltamath.com Help me please i really don't get it.

Brums [2.3K]

Answer:

cos = adjacent/hypotenuse

3/square root13

now you do square root 13 x3 divided by square root 13^2

= 3square root13/13

hope that answers your question

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2 years ago

Casandra is training for a 10 mile race. On the first day of running training she runs 4 miles, each day after that she adds on

ArbitrLikvidat [17]

Let the number of days needed be x.

First day = 4 miles = 3.5 + 0.5
Second day = 3.5 + 0.5(2)
Third day = 3.5 + 0.5(3)

Equation: 3.5 + 0.5x

Find the number of days needed to run 8 miles:
3.5 + 0.5x = 8
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x = 9

Answer: Casandra 8 miles on the 9th day.

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2 years ago