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solniwko [45]
2 years ago
7

Use the substitution method to determine the solution of the system of equations. y = -5x and 21x - 7y = 28

Mathematics
1 answer:
8_murik_8 [283]2 years ago
3 0

Answer:

x = 1/2   y = -5/2

Step-by-step explanation:

Since we already know an equation for y, we just need to plug it into the other equation.

21x - 7(-5x) = 28

21x + 35x = 28

56x = 28

x = 1/2

Now that we know x, we substitute it into the other equation, to find y.

y = -5x

y = -5(1/2)

= -5/2

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Write the equation 9y = 12x + 0.2 in standard form. Identify A, B, and C.
uysha [10]

Answer:

A = -12, B = 9 and C = .2

Step-by-step explanation:

So it just looks like we need to use algebra to move everything around to get it in the form Ax + By = C

So, let's start with 9y = 12x + 0.2.  From standard form we have all terms wth variables on one side, so let's do that.  the right sie has both a variable term and non variable term, so let's get rid of the variable term.  The variable term is 12x, so to get rid of it you subtract 12x from both sides.

9y = 12x + 0.2

9y - 12x = 0.2

To make it exactly in standard form just rarrnge.

-12x + 9y = 0.2

So now we have A = -12, B = 9 and C = .2

5 0
3 years ago
What is the sum of the interior angles of a 15-gon?
klemol [59]

Answer:

2340 degrees

Step-by-step explanation:

Each triangle has an angle sum of 180 degrees, therefore the sum of interior angles of 15-gon will be 13×180=2340

6 0
3 years ago
Please help with these two questions
S_A_V [24]
To answer question 12, you first need to know the definition of a <em>prism</em> and a<em> pyramid.

</em>A <em>pyramid </em> is a 3-D structure with one base, whose outer faces are made of triangles, and meet at a single point at the top.

A <em>prism</em> is any 3-D shape with a base of any number of sides, another base with the same amount of sides, and faces joining the two together on every side of the bases.

12.
Shape A is a <em>pyramid</em>, because it has one base, and all the faces join together in at one point.

Shape B is a <em>prism</em>, because it has two bases, and faces joining every side of the bases.

Shape C is a <em>prism.</em>

Shape D is a <em>pyramid.

</em>For #13, you have to know the definition of a cube to figure out the math of how many cubes there are.

A cube is a 3-D shape with six sides, all made up of squares of the same size.

The box has a volume of 120 cubic inches, and each cube is 1 inch. Since every side of a cube is equal, a 1-inch cube is one cubic inch.

This means that a box with a volume of 120 cubic inches will fit 120 of the 1 inch cubes.

1 layer of the cubes, in the diagram, is 8 cubes by 3 cubes, or 24 cubes total.

To find the number of layers needed to fill the box, you divide 120 by 24.

120 ÷ 24 = 5

The answer to #13 is 5 layers.
7 0
3 years ago
Reka Maharis drove her vehicle to and from work last year. Her records show a total of $1,560 for fixed costs and $3,740 for var
amid [387]

Answer: 5,300

Step-by-step explanation:

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2 years ago
What is the square root of 108 in simplified radical form?
Alenkinab [10]
\sqrt{108}=\sqrt{36 \times 3}=\sqrt{36} \times \sqrt{3}=6 \times \sqrt{3}=\boxed{6\sqrt{3}}
5 0
3 years ago
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