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julsineya [31]
3 years ago
11

A first number plus twice a second number is 9. Twice the first number plus the second totals 21. Find the numbers

Mathematics
1 answer:
WITCHER [35]3 years ago
7 0
Let x and y be the numbers;
We have x + 2y = 9 and 2x + y = 21;
Then, x = 9 - 2y;
Finally, 2(9-2y) + y = 21 ;
18 - 4y + y = 21;
18 - 3y = 21;
-3y = 3;
y = - 1;
x = 9 - 2× (-1);
x = 9 + 2 ;
x = 11;
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4g + 3(-3 + 4g) = 1-g. Solve the equation. Can someone help me ASAP. I'm confused
Olegator [25]
4g+3(-3+4g)=1-g
Distribute the 3(-3+4g)
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Add 4g and 12g
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17g-9=1
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Divide both sides by 17 and the answer is g=10/17
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3 years ago
How to find the central angle of a regular polygon
Annette [7]

Answer:

I hope this helps

Step-by-step explanation:

Central angle of a regular polygon:

The central angle of a polygon is the angle made at the center of a polygon by any two adjacent vertices as shown in the figure below.

In the above figure, the angles a, b, c, d, e and f are the central angles of the hexagon. There are 6 central angles in a hexagon. The number of central angles in a polygon is always equal to the number of sides of the polygon.

As you can see in the figure above, all the central angles of the polygon together will always form a complete circle. Hence the central angles add up to 360° in all polygons. Since a regular polygon has all equal sides, the central angles in a regular polygon are also equal.

So to find the measure of the central angles of a regular polygon follow the steps below:

First identify the number of sides ‘n’.

Then divide 360° by n.

For example: say you need to find the central angle of a regular pentagon.

First identify the number of sides ‘n’: here n = 5

Then divide 360° by n: 360° ÷ 5 = 72°.

Conversely, you can also find the number of sides of a regular polygon, when the central angle is given, by dividing 360 by the central angle.

Note: In the case of an irregular polygon, since there is no clear center for an irregular polygon, it has no central angle.

3 0
3 years ago
Which expression is equivalent to 3 + 3/8 − 1/2 ?
andreyandreev [35.5K]

Answer:

2 and 7/8

Step-by-step explanation:

3 + 3/8 - 1/2

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5 0
3 years ago
Help triangle sum therom and idk what to do
m_a_m_a [10]
Your answer would be x = 12

The triangle sum theorem states that the 3 angles in a triangle equal 180.

Since we have a 90 degree angle shown, we can add it to the other two and set it equal to 180.

30+90+6x-12=180
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3 years ago
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Anika [276]

Answer:

\large\boxed{x>3\to x\in(3,\ \infty)}

Step-by-step explanation:

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6 0
3 years ago
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