Question

Resolva as euquaçoes 

a)3x+9=12

b)3x-8=13

c)12x-10=5x+11

d)7x+5=68-2x

e)14-3x=2x+29

Answer 1

$a) \\ 3x + 9 = 12 \\ \\ 3x = 12 - 9 \\ \\ 3x = 3 \\ \\ x = \dfrac{3}{3} \\ \\ => x = 1$

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$b) \\ 3x - 8 = 13 \\ \\ \\ 3x = 13 + 8 \\ \\ 3x = 21 \\ \\ x = \frac{21}{3} \\ \\ => x = 7$

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$c) \\ 12x - 10 = 5x + 11 \\ \\ 12x - 5x = 11 + 10 \\ \\ 7x = 21 \\ \\ x = \dfrac{21}{7} \\ \\ => x = 3$

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$d) \\ 7x + 5 = 68 - 2x \\ \\ 7x + 2x = 68 - 5 \\ \\ 9x = 63 \\ \\ x = \dfrac{63}{9} \\ \\ => x = 7$

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$e) \\ 14-3x=2x+29 \\ \\ -3x - 2x = 29 - 14 \\ \\ -5x = 15 *(-1) \\ \\ 5x = -15 \\ \\ x = -\dfrac{15}{5} \\ \\ => x = -3$