Question

Resolva os sistemas :
a) {X+Y= 12
3X-Y=20

b) {X+Y =4
X-Y=8​

Answer 1

a)

{x + y = 12

{3x - y = 20

__________

4x = 32

x = 32 / 4

x = 8

y = 12 - X

y = 12 - 8

y = 4

(S) = { 8 , 4 }

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b)

{x + y = 4

{x - y = 8​

__________

2x = 12

x = 12/2

x = 6

x + y = 4

6 + y = 4

y = 4 - 6

y = - 2

(S) = {6, - 2}