Sistema de ecuaciones lineales

a + b = 135a – b = -35

a + b = 135a – b = - 352a = 100a = 100

2a = 50

+ a + b = 13550 + b = 135b = 135 – 50b = 85

a = 50b = 85

x + y = 72x – y = 48

x + y = 72x – y = 482x = 120x = 120

2x = 60

+x + y = 7260 + y = 72y = 72 – 60y = 12

x = 60y = 12

2x + 9y = 395x – y = -20

(5) 2x + 9y = 39(-2) 5x – y = -20

2x + 9y = 392x + 9(5) = 395x – y = -20 (-2) 5x – y = -20

10x + 45y = 195-10x + 2y = 4047y = 235

y = 23547

y = 5

x = -3y = 5

+

5x + 2y = 244x + 3y = 29

(4) 5x + 2y = 24(-5) 4x + 3y = 29

20x + 8y = 96-20x – 15y = -145

-7y = -49-y = -49

7-y = -7y = 7

x = 2y = 7

+

2x + 9(5) = 392x + 45 = 392x = 39 – 452x = -6x = 2

-6x = -3

5x + 2y = 245x + 2(7) = 245x + 14 = 245x = 24 – 145x = 10x = 10

5x = 2

8x - 3y = 177x - 4y = 8

x = 4y = 5

(7) 8x - 3y = 17(-8) 7x - 4y = 8

56x - 21y = 119-56x + 32y = -64

11y = 55y = 55

11y = 5

+

8x - 3y = 178x - 3(5) = 178x - 15 = 178x = 17 + 158x = 32x = 32

8x = 4

8x + y = 213x + y = 11

x = 2y = 5

(3) 8x + y = 21(8-) 3x + y = 11

24x + 3y = 63-24x - 8y = -88

-5y = -25-y = -25

5-y = -5y = 5

+

8x + y = 218x + 5 = 218x = 21 - 58x = 16x = 16

8x = 2

5x – 2y = 314x + 3y = 11

x = 5y = -3

(4) 5x – 2y = 31(-5) 4x + 3y = 11

20x - 8y = 124-20x - 15y = -55

-23y = 69-y = 69

23-y = 3y = -3

+

5x – 2y = 315x – 2(-3) = 315x + 6 = 315x = 31 - 65x = 25x = 25

5x = 5

5x – 6y = 21x - 2y = 5

x = 3y = -1

(1) 5x – 6y = 21(-5) x - 2y = 5

5x - 6y = 21-5x + 10y = -25

4y = -4y = -4

4y = -1

+

5x – 6y = 215x – 6(-1) = 215x + 6 = 215x = 21 - 65x = 15x = 15

5x = 3