Question

1-Determine o valor das incógnitas das seguintes equações:
a)4(x-2)=4+2(x-1)
b)10(x-1)-7(x+1)=4
c)3(1,4-x)+5x=-(x-4,8)
d)5(2x+7)-1=4(x-5)+9
e)2(x+1)+5(x-1)=7

Answer 1

$a) \\ \\ 4 (x - 2) = 4 + 2(x - 1) \\ \\ 4x - 8 = 4 + 2x - 2 \\ \\ 4x - 2x = 4 - 2 + 8 \\ \\ 2x = 10 \\ \\ x = \dfrac{10}{2} \\ \\ => x = 5$

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$b) \\ \\ 10(x - 1) - 7(x + 1) = 4 \\ \\ 10x - 10 - 7x - 7 = 4 \\ \\ 3x - 17 = 4 \\ \\ 3x = 4 + 17 \\ \\ 3x = 21 \\ \\ x = \dfrac{21}{3} \\ \\ => x = 7$

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$c) \\ \\ 3(1,4 - x) + 5x = - (x - 4,8) \\ \\4,2 - 3x + 5x = -x + 4,8 \\ \\ -3x + x = 4,8 - 4,2 \\ \\ -2x = 0,6 (-1) \\ \\ 2x = - 0,6 \\ \\ x = \frac{0,6}{2} \\ \\ => x = 0,3$

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$d) \\ \\ 5(2x + 7) - 1 = 4(x - 5) + 9 \\ \\ 10x + 35 - 1 = 4x - 20 + 9 \\ \\ 10x + 34 = 4x - 11 \\ \\ 10x - 4x = -11 - 34 \\ \\ 6x = -45 \\ \\ x = -\dfrac{45}{6}$

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$e) \\ \\ 2(x + 1) + 5(x - 1) = 7 \\ \\ 2x + 2 + 5x - 5 = 7 \\ \\ 7x - 3 = 7 \\ \\ 7x = 7 + 3 \\ \\ \\ 7x = 10 \\ \\=> x = \dfrac{10}{7}$