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tiny-mole [99]
4 years ago
8

7x+2y=-19 -x+2y=21 i need the substitution

Mathematics
1 answer:
alukav5142 [94]4 years ago
5 0
7x + 2y = 19
-x + 2y = 21

7x + 2y = 19
Subtract 2y from both sides
7x = 19 - 2y
Divide both sides by 7
x = (-2/7)y - (19/7)

x + 2y = 21
Substitute x for (-2/7)y - (19/7)
(-2/7)y - (19/7) + 2y = 21
Combine like terms
(12/7)y - (19/7) = 21
Add (19/7) to both sides
(12/7)y = (166/7)
Multiply both sides by (12/7)
y = (83/6)

x + 2y = 21
Substitute y for (83/6)
x + 2(83/6) = 21
Multiply 2 by (83/6)
x + (83/3) = 21
Subtract (83/3) from both sides
x = (-20/3)

x = (-20/3)
y = (83/6)
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Answer:

6 cm

Step-by-step explanation:

The diameter is 2x the radius

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Katy used 3/4 of a 6 ft board for a science fair project. How many inches did she use?
adoni [48]
She used 54 inches. 3/4 is equal to .75 so you can find 3/4 of the board by taking the fool length and multiplying it by .75 so 6•.75=4.5. So 3/4 of the board is 4.5 ft. However, the answer has to be in inches so since there are 12 inches in a foot you multiply 4.5•12 and that gives you your answer:54 inches.
5 0
3 years ago
Jessie draws triangle ABC on a coordinate grid. The slope of line segment AB is Jessie then transforms triangle
balu736 [363]

Answer:

1) Supports Jessie's Claim

2) Does Not Support Jessi's Claim

3) Supports Jessie's Claim

4) Does Not Support Jessi's Claim

Step-by-step explanation:

The given transformations are;

1) Rotation of 180° around the origin

For a rotation of 180° around the origin, either clockwise or anti clockwise, for a given coordinate of the preimage (x, y), the coordinate of the image is (-x, -y)

Therefore, whereby the slope of the preimage, given two points (0, 0) and (2, 2), = (2 - 0)/(2 - 0) = 1

For the image with the points (0, 0) and (-2, -2), we have;

(-2 - 0)/(-2 - 0) = 1

Therefore, the slope of the preimage and the image are equal

Therefore, supports Jessie's Claim

2) For a reflection across the line y = 2, we have

We note that the line y = 2 is parallel to the x-axis

For a reflection across the x-axis, for a preimage (x, y), we have the coordinates of the image (x, -y)

However for the reflection across the line y = 2, we have;

For a preimage, (x, y), the coordinate of the image is (x, -y+4)

Given two points, of the preimage (0, 0) and (2, 2), we have the image given as (0, 4) and (2, -2 + 4) = (2, 2);

The slope of the preimage is (2 - 0)/(2 - 0) = 1

The slope of the image is (2 - 4)/(2 - 0) = -1

The slope of the line of the preimage and the image are different

Therefore, does Not Support Jessi's Claim

3) For a translation up 1.25 units, we note that the difference in the y and x values of the coordinates of the preimage and the image will be equal when finding the slope, and therefore, the slope of the figure of the preimage and the slope of the figure of the image will be equal

Therefore, supports Jessie's Claim

4) For a reflection across the x-axis, a point on the preimage, with coordinates (x, y) will form a point on the image with coordinates (x, - y)

For a preimage with points (0, 0) and (2, 2), we have the image as (0, 0) and (2, -2)

The slope of the preimage is (2 - 0)/(2 - 0) = 1

The slope of the image is (-2 - 0)/(2 - 0) = -1

The slope of the line of the preimage and the image are different

Therefore, does Not Support Jessi's Claim

6 0
3 years ago
The inequality below compares two rational numbers. -8/18 > -17/27
astraxan [27]

Answer:

I have provided it below

Step-by-step explanation:

- 8/18 > - 17/27

- 0.444444 > 0.62963

So this inequality is TRUE

Hope this helps!!

6 0
3 years ago
Please help with this question?!?
erik [133]

Answer:

416 mi

Step-by-step explanation:

In order to find the surface area, you must find the area of each square. There are a total of 6 that make up the prism.

<em>Remember to find the area it is length x width</em>

  1. 9 x 8 = 72 which is the area for 4 of the squares. 2 on the side and 2 on the bottom
  2. Lastly for the last 2 squares to find the area you multiply 8 x 8 = 64
  3. In total, you will add 72+72+72+72+64+64 which equals 416

3 0
3 years ago
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