Ineed 100 points if right

use addition to solve the following systems.

7) 2x + 2y = 4

2x – 2y = 8

8) 2x + 4y = 5

3x – 4y = 10

multiply one of the equations to solve the systems.

9) 3x + 4y = 5

6x – 3y = -1

10) 2x - 2y = 5

4x + 6y = 5

7)(3,-1)

8. (3,-1/4)

9. (1/3,1)

10.(2,-1)

Step-by-step explanation:

7)2x + 2y = 4  

        2x – 2y = 8

         4x  = 12

Divide by 4

     4x/4 = 12/4

     x =3

Now we need to find y

2x+2y =4

2(3) + 2y =4

6+2y =4

Subtract 6 from each side

6-6 +2y = 4-6

2y = -2

Divide by 2

2y/2 = -2/2

y= -1

(3,-1)

8. 2x + 4y = 5  

   3x – 4y = 10

 5x    = 15

Divide by 5

5x/5 = 15/5

x=3

Now we need to find y

2x+4y = 5

2(3) +4y = 5

6+4y =5

Subtract 6 from each side

6-6+4y = 5-6

4y = -1

Divide by 4

4y/4 = -1/4

y = -1/4

(3,-1/4)

9.  3x + 4y = 5  

6x – 3y = -1

Multiply the first equation by -2

-2(3x + 4y) = 5*-2

-6x-8y = -10    

Now add this equation to the 2nd equation to eliminate x  

-6x-8y = -10    

6x – 3y = -1

-11y = -11

Divide by -11

-11y/-11 = -11/-11

y=1

Now we need to find x

3x+4y =5

3x+4(1) =5

3x+4=5

Subtract 4 from each side

3x+4-4 =5-4

3x = 1

Divide by 3

3x/3 = 1/3

(1/3,1)

10.  2x - 2y = 5  

4x + 6y = 5

Multiply the first equation by 3 to eliminate y

3( 2x - 2y) = 5  *3

6x -6y = 15

Now add this to the second equation

6x -6y = 15

4x + 6y = 5

10x = 20

Divide by 10

10x/10 = 20/10

x=2

Now we need to find y

4x+6y=5

4(2) +6y = 5

8+6y = 5

Subtract 8 from each side

8-8+6y=5-8

6y = -3

Divide by 6

6y/6 = -3/6

y=-1/2

(2,-1/2)

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step-by-step explanation: