Question

Mostre o valor de X e Y

A)
${4x - y = 20 \\ 6x + y = 30$


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Answer 1

4x - y = 30

206x + y = 30 -> y = 30 - 206x

4x - y = 30

4x - (30 - 206x) = 30

4x -30 + 206x = 30

210x = 30 + 30

x = 60/210

x = 6/21

4x - y = 30

4 . (6/21) - y = 30

24/21 - y = 30

24/21 - 30 = y

y = 24/21 - 30

y = (24 - 630)/21

y = -606/21

y = -202/7

Resposta: X vale 6/21 ;  y vale -202/7