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1 year ago

7

Solve the system of equations – 5x + y = 56 and x + y = -4 by combining the equations.

2 answers:

anygoal [31]1 year ago

5 0

Answer:

Your solution is (-10, 6).

Step-by-step explanation:

Combining the equations is also known as substitution. This is done when you substitute one variable into another equation.

-5x + y = 56

x + y = -4

Let's change the second equation into one with one variable on each side.

y = -x - 4

Now, plug this into your first equation.

-5x + (-x - 4) = 56

Distribute the + sign.

-5x - x - 4 = 56

Combine the like terms.

-6x - 4 = 56

-6x = 60

Isolate x by dividing both sides by -6.

x = -10

Now plug this back into either equation.

-10 + y = -4

Add 10 to both sides to find y.

y = 6

Your solution is (-10, 6).

Check this by plugging in these values into the equation you have not checked yet.

-5(-10) + (6) = 56

50 + 6 = 56

56 = 56

Your solution is correct.

Hope this helps!

Goryan [66]1 year ago

5 0

Answer:

x=-10; y=6

Step-by-step explanation:

combine the equations:

-5x + y + x + y = 56 +(-4)

-4x + 2y = 52

add 4x to each side

2y=52+4x

divide by 2

y=26+2x

now substitute 26+2x for y in the second equation:

x + 26 + 2x = -4

3x + 26 = -4

3x = -30

x = -10

therefore y = 6

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Express 25.6 nanometres in metres, giving your answer in standard form.

zhannawk [14.2K]

Answer:

10 to power of -8 so 0.00000001 I think

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2 years ago

Z to the power of 2 =1

stiv31 [10]

That would be written as:

$z^{2} = 1$

And the step-by-step equation would be:

$z^{2} = 1$ → we take the 2 to the right side of the equation and do the IO*

$z = \sqrt{1}$ →we solve for $\sqrt{1}$

$z = 1$ → final answer

*Ps - IO is not an existing term and stands for inverse operation. In this case, because when we take to 2 to the right side of the equation (the 2 is a power) it'll have to turn into a square root (because exponents and roots are inverse operations)

Hope it helped,

BioTeacher101

3 0

2 years ago

Last year your professor wanted to study the pattern in class grades. The following table contains a sample of grades collected

Maslowich

Answer:

mean = 78.4

median = 77.5

mode = 75

This is Right - skewed (positive skewness) distribution

Step-by-step explanation:

<u>Mean:-</u>

The mean (average) is found by adding all of the numbers together and dividing by the number of items and it is denoted by x⁻

mean = $\frac{64+80+75+98+75}{5}$

mean (x⁻ ) = 78.4

The mean of the given data = 78.4

<u>Median:</u>

The median is found by ordering the set from lowest to highest and finding the exact middle.

64 ,75, 80, 98

The middle term of the given data set = $\frac{75+80}{2} =77.5$

<u>Mode :</u>

The mode is the most common repeated number in a data set.

64 ,75, 75, 80, 98

in data the most common number = 75

<u>Conclusion</u>:-

mean = 78.4

median = 77.5

mode = 75

This is Right - skewed (positive skewness) distribution

8 0

2 years ago

1. The following are the number of hours that 10 police officers have spent being trained in how to handle encounters with peopl

dusya [7]

Answer:

$Range = 16$

$Inter\ Quartile\ Range = 6.75$

$Variance = 20.44$

$Standard\ Deviation = 4.52$

Step-by-step explanation:

Given

4, 17, 12, 9, 6, 10, 1, 5, 9, 3

Calculating the range;

$Range = Highest - Lowest$

From the given data;

Highest = 17 and Lowest = 1

Hence;

$Range = 17 - 1$

$Range = 16$

Calculating the Inter-quartile Range

Inter quartile range (IQR) is calculates as thus

$IQR = Q_3 - Q_1$

Where

Q3 = Upper Quartile and Q1 = Lower Quartile

<em />

<em>Start by arranging the data in ascending order</em>

1, 3, 4, 5, 6, 9, 9, 10, 12, 17

N = Number of data; N = 10

---------------------------------------------------------------------------------

Calculating Q3

$Q_3 = \frac{3}{4}(N+1) th\ item$

<em>Substitute 10 for N</em>

$Q_3 = \frac{3}{4}(10+1) th\ item$

$Q_3 = \frac{3}{4}(11) th\ item$

$Q_3 = \frac{33}{4} th\ item$

$Q_3 = 8.25 th\ item$

Express 8.25 as 8 + 0.25

$Q_3 = (8 + 0.25) th\ item$

$Q_3 = 8th\ item + 0.25 th\ item$

Express 0.25 as fraction

$Q_3 = 8th\ item +\frac{1}{4} th\ item$

$Q_3 = 8th\ item +\frac{1}{4} (9th\ item - 8th\ item)$

From the arranged data;

$8th\ item = 10$ and $9th\ item = 12$

$Q_3 = 8th\ item +\frac{1}{4} (9th\ item - 8th\ item)$

$Q_3 = 10 +\frac{1}{4} (12 - 10)$

$Q_3 = 10 +\frac{1}{4} (2)$

$Q_3 = 10 +0.5$

$Q_3 = 10.5$

Calculating Q1

$Q_1 = \frac{1}{4}(N+1) th\ item$

<em>Substitute 10 for N</em>

$Q_1 = \frac{1}{4}(10+1) th\ item$

$Q_1 = \frac{1}{4}(11) th\ item$

$Q_1 = \frac{11}{4} th\ item$

$Q_1 = 2.75 th\ item$

Express 2.75 as 2 + 0.75

$Q_1 = (2 + 0.75) th\ item$

$Q_1 = 2nd\ item + 0.75 th\ item$

Express 0.75 as fraction

$Q_1 = 2nd\ item +\frac{3}{4} th\ item$

$Q_1 = 2nd\ item +\frac{3}{4} (3rd\ item - 2nd\ item)$

From the arranged data;

$2nd\ item = 3$ and $3rd\ item = 4$

$Q_1 = 3 +\frac{3}{4} (4 - 3)$

$Q_1 = 3 +\frac{3}{4} (1)$

$Q_1 = 3 +0.75$

$Q_1 = 3 .75$

---------------------------------------------------------------------------------

Recall that

$IQR = Q_3 - Q_1$

$IQR = 10.5 - 3.75$

$IQR = 6.75$

Calculating Variance

Start by calculating the mean

$Mean = \frac{1+3+4+5+6+9+9+10+12+17}{10}$

$Mean = \frac{76}{10}$

$Mean = 7.6$

Subtract the mean from each data, then square the result

$(1 - 7.6)^2 = (-6.6)^2 = 43.56$

$(3 - 7.6)^2 = (-4.6)^2 = 21.16$

$(4 - 7.6)^2 = (-3.6)^2 = 12.96$

$(5 - 7.6)^2 = (-2.6)^2 = 6.76$

$(6 - 7.6)^2 = (-1.6)^2 = 2.56$

$(9 - 7.6)^2 = (1.4)^2 = 1.96$

$(9 - 7.6)^2 = (1.4)^2 = 1.96$

$(10 - 7.6)^2 = (2.4)^2 = 5.76$

$(12 - 7.6)^2 = (4.4)^2 = 19.36$

$(17 - 7.6)^2 = (9.4)^2 = 88.36$

Sum the result

$43.56 + 21.16 + 12.96 + 6.76 + 2.56 + 1.96 + 1.96 + 5.76 + 19.36 + 88.36 = 204.4$

Divide by number of observation;

$Variance = \frac{204.4}{10}$

$Variance = 20.44$

Calculating Standard Deviation (SD)

$SD = \sqrt{Variance}$

$SD = \sqrt{20.44}$

$SD = 4.52$ <em>(Approximated)</em>

4 0

2 years ago

A man bought a mobile phone for $800 and sold it for $1000. What was his profit as a percentage of the cost price

bija089 [108]

Answer:

1000/800 = 125% profit

5 0

2 years ago

Read 2 more answers