Question

5-Resolva as seguintes equaçoes do primeiro grau e tire a prova da resoluçao .
a)x+4=12
b)x-12=20
c)4x+2=10
d)-3x=-9
e)3x+12=27
f)x+4=15
g)5-(4x+2)=8+2(x-1)

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Answer 1

$x + 4 = 12 \\ x = 12 - 4 = 8 \\ 8 + 4 = 12$

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$x - 12 = 20 \\ x = 20 + 12 \\ x = 32 \\ 32 - 12 = 20$

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$4x + 2 = 10 \\ 4x = 10 - 2 = 8 \\ x = 2 \\ 8 + 2 = 10$

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$- 3x = - 9 \\ x = 9 \div 3 = 3 \\ 3 \times - 3 = - 9$

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$3x + 12 = 27 \\ 3x = 27 - 12 = 15 \\ x = 5 \\ 5(3) + 12 = 17 \\ 15 + 12 = 27$

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$x + 4 = 15 \\ x = 15 - 4 \\ x = 11 \\ 11 + 4 = 15$

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$5 - (4x + 2) = 8 +2 (x - 1) \\ 5 - 4x - 2 = 8 + 2x - 2 \\ - 4x - 2x = 8 - 2 + 2 - 5 \\ - 6x = 3 \\ \\ x = - \frac{3}{6} = - \frac{1}{2} \\ \\ 5 - ( - 2 + 2) = 8 - 1 - 2 \\ 5 = 5$