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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

You might be interested in
500 plates cost $18.00 what does each plate cost​
ozzi

Answer:

$0.036

Step-by-step explanation:

I will be solving this questions in a rational, proportional way.

This question given is directly proportional. There are two types of proportion.

Direct - Let's say there are two values, x and y. In direct proportion, while x   increases, y increases with it.  

Inverse- Taking x and y, in inverse proportion, while x increases, y decreases or while y increases, x decreases.

In the given example, there are two values, number of plates and cost of plates. While the number of plates increases, the cost would surely increase. Therefore, giving us that it is a direct proportion.

500 plates : $18.00 :: 1 : $x

500 plates is to 18 dollars, then, 1 plate is to how many dollars?

In direct proportion, the product of extremes is equal to the product of means.

500(x) = 18(1)

500x = 18

x = 18 / 500

x = 0.036

Hence, one plate costs $0.036 or 3.6 cents

5 0
3 years ago
Read 2 more answers
Jimmy's school is selling tickets to the
natka813 [3]
Children’s tickets are $4, adult tickets are $14




Explanation:

4a+6c=80

If they made $4 more dollars on the second day than the first by selling one extra child ticket then we know a child’s ticket is $4 per ticket.


4a+6*4=80
4a+24=80
4a=56
14=a

So each adult ticket costs $14.


You can check by filling in $14 and $4 for each equation.


4*14+6*4=80

4*14+7*4=84
3 0
2 years ago
2 inches in 5 seconds Part A Find the unit rate.
Vera_Pavlovna [14]

rate = distance / time Ok, part a is correct, try writing the answer as 2/5

rate = 2/5 = 0.4 in/s

rate = 0.4 in/s

Hi, I'm here is just that the pictures are small, I'm trying to read them

b)

Please upload a picture of part b like the last picture you sent of part a

2/5 = x/ 15

x = 15 x 2 / 5

x = 30/5

x = 6 inches

The result is 6

3 0
1 year ago
I need help with these two questions please!
Novay_Z [31]
The first one is rectangle
6 0
3 years ago
Read 2 more answers
PLZZZ HELP WILL MAKE BRAINLY
attashe74 [19]

Answer:

56

Step-by-step explanation:

To divide 364 into two parts in the ratio 15:11, add 15+11 to get 26. Now divide 364 by 26 to get 14. This counters 14 for each part, and we have 26 parts. If each part is x, and x=14, x times 15 will equal 15x=210, so the first number is 210. x times 11 will equal 11x=154, so the second number is 154. 210-154=56, so the first number is 56 bigger than the second.

4 0
3 years ago
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