polígrafo

1. SOLUC¸ ˜AO DE EQUAC¸ ˜OES
Prof. Dr. Carlos A. P. Campani
PROPRIEDADES COMO UMA BALANC¸ A COM FIEL
α = β
α = β ⇒ β = α
α = β ⇒ aα = aβ a ∈ R
α = β ⇒ α + a = β + a a ∈ R
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2. EXEMPLO DE SOLUC¸ ˜AO
2(x − 1) +
3
2
− x = 3
2x − 2 +
3
2
− x = 3 [prop. distributiva]
MMC(1, 2) = 2
2 2x − 2 +
3
2
− x = 2.3 [prop. das equa¸c˜oes]
4x − 4 + 3 − 2x = 6 [prop. distributiva]
4x + ((−4) + 3) − 2x = 6 [prop. associativa]
4x − 1 − 2x = 6 [simplifica¸c˜ao]
4x + ((−1) + (−2x)) = 6 [prop. associativa]
4x + ((−2x) + (−1)) = 6 [prop. comutativa]
(4x − 2x) − 1 = 6 [prop. associativa]
2x − 1 = 6 [simplifica¸c˜ao]
2x − 1 + 1 = 6 + 1 [prop. equa¸c˜oes]
2x + ((−1) + 1) = 6 + 1 [prop. associativa]
2x = 7 [simplifica¸c˜ao]
1
2
2x =
1
2
7 [prop. das equa¸c˜oes]
1.x =
7
2
[simplifica¸c˜ao]
x =
7
2
[elemento neutro da multiplica¸c˜ao]
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