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kakasveta [241]
3 years ago
14

What is the solution to this using substitution method pls show ur work

Mathematics
1 answer:
VARVARA [1.3K]3 years ago
4 0

Answer:

x=-6, y=0

Step-by-step explanation:

Use the 3x-9y=-18 equation and add 9y to both sides to have 3x on its own on the left side. Then, divide by 3 on both sides. Then you'll have x=-6+3y. Plus this back into the 5x+4y=-30 equation and you'll get 5(-6+3y)+4y=-30. Use the distributive property and you'll get -30+15y+4y=-30. Simplify and get -30+19y=-30, then add 30 to both sides and you'll get 19y=0. Divide by 19 on both sides and you'll get y=0. Now that we know y=0, plug that back into the 5x+4y=-30 equation, and you'll get 5x+4(0)=-30. Simplify and you'll get 5x=-30. Divide by 5 on both sides and you'll get x=-6.

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The graph of an absolute value function contains the points (–3, 5), (0, 2) and (3, 5). Which could be the function represented
Alex73 [517]

The absolute value functions that contains the points are:

  • f(x) = |x| + 2
  • f(x) = |-x| + 2

<h3>Which could be the function represented by this graph?</h3>

Here we have the points (-3, 5), (0, 2), and (3, 5). We want to see which ones of the given functions have that points.

To check that, we need to evaluate the functions in the first value of each point and see if the outcome is the second value of the correspondent point.

For example, for the first equation:

  • f(-3) = |-3| + 2 = 5   so it has the point (-3, 5)
  • f(0) = |0| + 2 = 2  so it has the point (0, 2)
  • f(3) = |3| + 2 = 5  so it has the point (3, 5).

The other option that also contains these 3 points is:

f(x) = |-x| + 2

  • f(-3) = |3| + 2 = 5  so it has the point (-3, 5)
  • f(0) = |-0| + 2 = 2  so it has the point (0, 2)
  • f(3) =  |-3| + 2 = 5  so it has the point (3, 5).

And all the other options can be trivially discarded (by evaluating them).

So the two correct options are:

  • f(x) = |x| + 2
  • f(x) = |-x| + 2

If you want to learn more about absolute value functions:

brainly.com/question/3381225

#SPJ1

4 0
2 years ago
A line of best fit predicts that when x equals 30, y will equal 34.215, but y actually equals 32. What is the residual in this c
Katarina [22]

Answer: A. - 2.215

Step-by-step explanation:

• A residual is the difference between the actual value and the predicted value in a regression model. It represents the vertical distance from the actual point to the point on the regression line.

\text{Residual=Actual value of y -predicted value of y}\\\\\Rightarrow\text{Residual}=32-34.215\\\\\Rightarrow\text{Residual}=-2.215

Hence, the residual in this case = -2.215

4 0
3 years ago
Classify the area of a circle with a radius of 0.75 centimeter seems as either rational or irrational
Mazyrski [523]
Irrational as 0.75 x 0.75 x 3.14......
8 0
3 years ago
2. A random sample of 30 households was selected as part of a study on electricity usage, and the number of kilowatt-hours (kWh)
Brrunno [24]

Answer:

Step-by-step explanation:

Given that n =30, x bar = 375 and sigma = 81

Normal distribution is assumed and population std dev is known

Hence z critical values can be used.

For 95% Z critical=1.96

Margin of error = 1.96(\frac{81}{\sqrt{30} } )=29

Confidence interval = 375±29

=(346,404)

B) 99% confidence

Margin of error = 2.59*Std error =38

Confidence interval = 375±38

=(337, 413)

C) For 90%

Margin of error = 20

Std error = 20/1.645 = 12.158

Sample size

n=(\frac{81}{12.158} )^2\\=44.38

Atleast 44 people should be sample size.

8 0
3 years ago
When a number is doubled and 5 is subtaracted from the result,the answer is 37.what is the number?
Dvinal [7]
The number would be 21 because if you add 5+37 then divide by 2.Younwill get the answer
6 0
3 years ago
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