Question

Resolva os sistemas
a){10y=10x+30
{x+2y=3

Answer 1

-10x + 10y = 30
x + 2y = 3 (*10)
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-10x + 10y = 30
10x + 20y = 30
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30y = 60
y = 60/30
y = 2

-10x + 10y = 30
-10x + 10(2) = 30
-10x + 20 = 30
-10x = 30 - 20
-10x = 10
x = -10/10
x = -1

Tirando a prova temos:

-10x + 10y = 30
-10(-1) + 10(2) = 30
10 + 20 = 30
30 = 30

x + 2y = 3 
-1 + 2(2) = 3
-1 + 4 = 3
3 = 3