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3 years ago

Solve 5x+4y=-30 3x-9y=-18 Solve using the elimination method

Mathematics

1 answer:

jenyasd209 [6]3 years ago

4 0

Answer:

(x, y) = (-6, 0)

Step-by-step explanation:

The y-coefficients have opposite signs, so we can eliminate y-terms by multiplying both equations by a positive number and adding the results.

9 times the first equation plus 4 times the second gives ...

9(5x +4y) +4(3x -9y) = 9(-30) +4(-18)

45x +36y +12x -36y = -270 -72 . . . . eliminate parentheses

57x = -342 . . . . . collect terms

x = -6 . . . . . . . divide by the coefficient of x

Substituting into the first equation gives ...

5(-6) +4y = -30

4y = 0 . . . . . . . . . add 30

y = 0

The solution is (x, y) = (-6, 0).

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Find the image of z(1,1) after two reflections, first across line l1, and then across line l2.

jok3333 [9.3K]

We conclude that the coordinates after two reflections are (-3, 1)

<h3>How to find the image after the two reflections?</h3>

A reflection across a line moves a point perpendicularly towards that line and translates it to the other side of the line, such that the distance between the point and the line doesn't change.

Here the original point is z(1, 1)

And the first reflection is across line x = 2.

This is a vertical line, then it only will change the x-value.

Now, the distance between the x-value of our point and the line is:

|2 - 1| = 1

The new x-value will be one that is at a distance of 1 unit of the number 2 (a number different than 1, which is the x-value before the reflection).

That value will be x = 3.

|2 - 3| = |-1| = 1

Then the new point is (3, 1)

Now we do another reflection across the y-axis. This only changes the sign of the x-value, then we will get:

(-3, 1)

We conclude that the coordinates after two reflections are (-3, 1).

If you want to learn more about reflections.

brainly.com/question/4289712

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3 0

2 years ago

Find the sum 5,-7 <br> A. 2 <br> B. -2 <br> C. -35 <br> D. 12

igomit [66]

5-7 is your question.
When you have a negative and a positive number and you are adding them, the negative number is going to be diminished by how many positive numbers you have. If we find the absolute value of both numbers and then subtract them we will get a smaller number.
The absolute value of -7 is 7.
The absolute value of 5 is 5.
So now we will subtract 5 from 7 and we get 2.
To find out if it is negative or positive we look at the absolute values of our original numbers.
Which one is greater? 7 or 5?
7 is the greater number.
7 was originally a negative.
Since this had the greatest absolute value we use this numbers original sign. Which is negative.
So your final answer is B. -2.

7 0

4 years ago

Read 2 more answers

The sixth-graders at Meadowbrook Middle School are going on a field trip. The 325 students and adults will ride in school buses.

Tom [10]

7, you divide 325 by 48. You get 6.77... since this is a real-world problem, you can’t have 6 and 2/3 buses so you round.

8 0

3 years ago

Read 2 more answers

dolphi86 [110]

Answer:

x = 27/8

Step-by-step explanation:

We can write a ratio to solve

x 3

------- = ----------

x+9 11

Using cross products

x*11 = 3(x+9)

11x = 3x+27

Subtract 3x from each side

8x = 27

8x/8 = 27/8

x = 27/8

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3 years ago

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deff fn [24]

Answer:

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Step-by-step explanation:

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3 years ago