148k views
24 votes
What are the answers for these 11, 14, 15, 16 and 20.

What are the answers for these 11, 14, 15, 16 and 20.-example-1

1 Answer

4 votes

Answer:

11. (x, y) -> (7, -3)

14. (x, y) -> (-3, -2)

15. (x, y) -> (-3, 2)

16. (x, y) -> (7,6)

20.(x, y) -> (4, 1)

Explanation:

11.

x + 3y = 1

-3x -3y = -15

-2x = -14

/-2 /-2

x = 7

x + 3y = 1

7 + 3y = 1

-7 -7

3y = -6

/3 /3

y = -2

(x, y) -> (7, -3)

14.

-3x + 3y = 3

-5x + y = 13

-5x + y = 13

+5x +5x

y = 5x + 13

-3x + 3(5x + 13) = 3

-3x + 15x + 39 = 3

12x + 39 = 3

- 39 -39

12x = -36

/12 /12

x = -3

Now, we solve for y:

-5x + y = 13

-5(-3) + y = 13

15 + y = 13

-15 -15

y = -2

(x, y) -> (-3, -2)

15.

6x + 6y = -6

5x + y = -13

5x + y = -13

-5x -5x

y = -5x - 13

6x + 6y = -6

6x + 6(-5x - 13) = -6

6x -30x - 78 = -6

-24x - 78 = -6

+ 78 + 78

-24x = 72

/-24 /-24

x = -3

Now, we solve for y:

6x + 6y = -6

6x + 6y = -6

6(-3) + 6y = -6

-18 + 6y = -6

+18 +18

6y = 12

/6 /6

y = 2

(x, y) -> (-3, 2)

16.

2x + y = 20

6x - 5y = 12

2x + y = 20

-2x -2x

y = -2x + 20

6x - 5y = 12

6x - 5(-2x + 20) = 12

6x + 10x - 100 = 12

16x - 100 = 12

+ 100 +100

16x = 112

/16 /16

x = 7

Now, we solve for y:

2x + y = 20

2(7) + y = 20

14 + y = 20

-14 -14

y = 6

(x, y) -> (7,6)

20.

-2x - y = -9

5x - 2y = 18

-2x - y = -9

+2x +2x

-y = 2x - 9

/-1 /-1

y = -2x + 9

5x -2y = 18

5x - 2(-2x + 9) = 18

5x + 4x - 18 = 18

9x - 18 = 18

+ 18 + 18

9x = 36

/9 /9

x = 4

Now, we solve for y:

-2(4) - y = -9

-8 - y = -9

+ 8 +8

-y = -1

/-1 /-1

y = 1

(x, y) -> (4, 1)

Hope this helps!

What are the answers for these 11, 14, 15, 16 and 20.-example-1
What are the answers for these 11, 14, 15, 16 and 20.-example-2
What are the answers for these 11, 14, 15, 16 and 20.-example-3
What are the answers for these 11, 14, 15, 16 and 20.-example-4
What are the answers for these 11, 14, 15, 16 and 20.-example-5
User Giuliolunati
by
7.2k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories