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Charra [1.4K]
3 years ago
7

I DONT KNOW THESE! HELP!

Mathematics
1 answer:
kkurt [141]3 years ago
3 0

Answer:

20. x = 5, y = -2

21. x = 11, y = 12

22. x = 22, y = 11

23. x = 11, y = 10

Step-by-step explanation:

20. Opposite sides in the parallelogram are congruent, so

2y+18=3x-1\\ \\6x-3=17-5y

Solve this system of two equations:

\left\{\begin{array}{l}2y-3x=-19\\ \\6x+5y=20\end{array}\right.

Multiply the first equation by 2 and add two equations:

2(2y-3x)+6x+5y=2\cdot (-19)+20\\ \\4y-6x+6x+5y=-38+20\\ \\9y=-18\\ \\y=-2

Substitute it into the first equation:

2\cdot (-2)-3x=-19\\ \\-3x=-19+4\\ \\-3x=-15\\ \\x=5

21. Opposite angles in the parallelogram are congruent, so

11x+5=10y+6

Consecutive angles are supplementary, so

6x-y+11x+5=180^{\circ}

Solve this system of two equations:

\left\{\begin{array}{l}11x-10y=1\\ \\17x-y=175\end{array}\right.

From the second equation

y=17x-175

Substitute it into the first equation:

11x-10(17x-175)=1\\ \\11x-170x+1750=1\\ \\-159x=-1749\\ \\x=11\\ \\y=17\cdot 11-175=187-175=12

22. Opposite angles in the parallelogram are congruent, so

2x-5=3y-12

Consecutive angles are supplementary, so

2x-5+7y+x=180^{\circ}

Solve this system of two equations:

\left\{\begin{array}{l}2x-3y=-7\\ \\3x+7y=185\end{array}\right.

From the first equation

x=-3.5+1.5y

Substitute it into the second equation:

3(-3.5+1.5y)+7y=185\\ \\-10.5+4.5y+7y=185\\ \\-105+45y+70y=1,850\\ \\115y=1,850+105\\ \\115y=1,955\\ \\y=17\\ \\x=-3.5+1.5\cdot 17=22

23. Opposite sides in the parallelogram are congruent, so

2x+9=4y-9\\ \\3x-5=2y+8

Solve this system of two equations:

\left\{\begin{array}{l}2x-4y=-18\\ \\3x-2y=13\end{array}\right.

Multiply the second equation by 2 and subtract it from the first equation:

2x-4y-2(3x-2y)=-18-2\cdot 13\\ \\2x-4y-6x+4y=-18-26\\ \\-4x=-44\\ \\x=11

Substitute it into the first equation:

2\cdot 11-4y=-18\\ \\-4y=-18-22\\ \\-4y=-40\\ \\y=10

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guajiro [1.7K]

Answer:

D

Step-by-step explanation:

If I estmaite the answer from 81% to 80%, then 80*2=160. 160/2=80. 80% to 81 percent.

--------------------------------------------------------------------------------

Hope this helps you...

6 0
3 years ago
What is the hundred digits of pi?​
Naya [18.7K]

Answer:

3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679

Step-by-step explanation:

7 0
3 years ago
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What is 6/15 written as a decimal?
Allushta [10]
It will be C cause you divid 15 and 6
3 0
3 years ago
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Please simplify this please it’s due really soon!
iren2701 [21]

Step-by-step explanation:

\frac{ {13}^{6}  \div  {13}^{8}  \times  {13}^{ - 4} }{ {13}^{ - 2} }

You need to remember the properties of exponents: multiplication adds the exponents, division subtracts the exponents.

If you multiply two powers with the same base, the result will be the base to the sum of the powers.

If you divide two powers with the same base, the result will be the base to the difference of the powers.

In your case you will this:

{13}^{6 - 8 + ( - 4) - ( - 2)}

That is:

{13}^{ - 4}

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7 0
3 years ago
What is the length of the blue in the circle<br> o below
iVinArrow [24]

Answer:

Option D. 8.53 units

Step-by-step explanation:

we know that

The triangle OAB is congruent with the triangle OCD

because

OA=OB=OC=OD=radius circle O

AB=CD

therefore

The height of both triangles is equal to 8.53 units

The segment blue is equal to 8.53 units

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