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Makovka662 [10]
3 years ago
8

WILL AWARD BRAINLIEST!!! there are 4 questions.

Mathematics
1 answer:
Karolina [17]3 years ago
6 0
D
A
B
B
These are the correct answers
You might be interested in
Please help me on this question I really need help. :,)
Kazeer [188]

Answer:

a. (7, 27) Polly was incorrect.

b. (3, 1) Polly was correct.

Step-by-step explanation:

a.

y = 4x - 1

2x - y = -13

We can solve this by substitution. Our first equation gives us y. Plug that into our second equation for each instance of y.

2x - y = -13

2x - (4x - 1) = -13

First distribute the negative sign across the parentheses.

2x - 4x + 1 = -13

Combine like terms.

-2x + 1 = -13

-2x = -14

Divide both sides by -2.

x = 7

Now that we know x, plug its value into one of our original equations.

y = 4x - 1

y = 4(7) - 1

Solve.

y = 28 - 1

y = 27

Our solution is (7, 27).

Let's check our answer by plugging both values into one of our original equations.

2x - y = -13

2(7) - 27 = -13

Solve.

14 - 27 = -13

-13 = -13

Your solution is correct.

Polly's solution was (-2, -9), which is incorrect.

b.

3x + 6y = 15

-2x + 3y = -3

Let's solve this by elimination. To solve by elimination means to eliminate a variable from the equation.

We have 3x & -2x and 6y & 3y. Notice that 6 and 3 can be simplified easily. To eliminate y, we want to multiply each factor of the second equation by -2.

-2x + 3y = -3

-2(-2x + 3y = -3)

4x - 6y = 6

Write the equations together.

3x + 6y = 15

4x - 6y = 6

Now we can see that the y variable will cancel out.

Apply the elimination method.

3x + 6y = 15

4x - 6y = 6

________

7x = 21

Divide both sides by 7.

x = 3

Now that we know x, plug its value into one of our original equations.

3x + 6y = 15

3(3) + 6y = 15

Solve.

9 + 6y = 15

6y = 15 - 9

6y = 6

y = 1

Our solution is (3, 1).

Let's check our answer by plugging both values into one of our original equations.

-2x + 3y = -3

-2(3) + 3(1) = -3

Solve.

-6 + 3 = -3

-3 = -3

Your solution is correct.

Polly's solution was (3, 1), so she was correct.

Hope this helps!

6 0
2 years ago
I need answer on this problem tyt​
tamaranim1 [39]
<h3>Speed of light:</h3>

3.05 \times 10 ^{8} m/s

<h3 /><h3>Seconds in a year:</h3>

3.15 \times 10 ^{7}

\rule{300pt}{3pt}

Multiply the speed of light with seconds in a year

*Note:- We will not change the values because speed of light is in m/s and the time is also given in seconds.

\rule{300pt}{3pt}

3.08 \times 10 ^{8}  \times 3.15 \times 10 ^{7}

(3.05 \times 3.15) \times (10 ^{8}  \times 10 ^{7} )

9.4675 \times 10 ^{15}

\tt9.46 \: Trillion \: Kilometers

3 0
2 years ago
X+8/4 = -6 a.x = -32 b.x = 16 c.x = -16 d.x = -24 a. Hurryyyyy i need helppppppppp
son4ous [18]

Answer:

x = -8

Step-by-step explanation:

x + (8/4) = -6

x × 4 + (8/4) × 4 = -6 × 4

4x + 8 = -24

4x = -24 - 8

4x = -32

x = -8

6 0
3 years ago
The length of one leg of a right triangle is 20.3 centimeters. The length of the hypotenuse is
meriva
<h3>Answer:  Approximately 23.0 cm</h3>

=====================================================

Work Shown:

a = 20.3

b = unknown

c = 30.7

Apply the pythagorean theorem to find b

a^2 + b^2 = c^2

(20.3)^2 + b^2 = (30.7)^2

412.09 + b^2 = 942.49

b^2 = 942.49-412.09

b^2 = 530.4

b = sqrt(530.4)

b = 23.0304146727757  value is approximate

b = 23.0

I rounded to one decimal place because the other values (20.3 and 30.7) were to one decimal place.

8 0
2 years ago
Write cos 53 degrees in terms of sine.
SOVA2 [1]
Cos(x) = sin(90 - x)
cos(53) = sin(90 - 53)
cos(53) = sin(37)
7 0
3 years ago
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