Question

Qual equação o valor de X é 5 ?

8x + 15 = 3x + 45
6x - 8 + x = 13 + 2x + 4
7x - 3x -34 = 2x + 46 - 20
20 + 3x - 5 = 2x + 15​

Answer 1

A)

$8x + 15 = 3x + 45$

$8x - 3x + 15 \: = \: 45$

$8x - 3x = \: 45 \: - \: 15$

$5x = \: 45 \: - \: 15$

$5x = 30$

$x = \frac{30}{5}$

$x = 6$

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B)

$6x - 8 + x = 13 + 2x + 4$

$7x - 8 = 13 + 2x + 4$

$7x - 8 = 17 + 2x$

$7x - 2x - 8 = 17$

$7x - 2x = 17 + 8$

$5x = 17 + 8$

$5x = 25$

$x = \frac{25}{5}$

$x = 5$

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C)

$7x - 3x -34 = 2x + 46 - 20$

$4x -34 = 2x + 46 - 20$

$4x -34 = 2x + 26$

$4x - 2x \: -34 = 26$

$4x - 2x = 26 \: + 34$

$2x = 26 \: + 34$

$2x = 60$

$x = \frac{60}{2}$

$x = 30$

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D)

$20 + 3x - 5 = 2x + 15$

$15 + 3x = 2x + 15$

$3x = 2x$

$3x - 2x = 0$

$x = 0$