Question

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Answer 1

I в.

1)

$3 - 5x = 0 \\ - 5x = - 3 \\ x = \frac{ - 3}{ - 5} \\ x = 0.6$

2)

$8x - 5 = x - 40 \\ 8x - x = - 40 + 5 \\ 7x = - 35 \\ x = \frac{ - 35}{7} \\ x = - 5$

3)

$6x + (3x - 4) = 14 \\ 6x + 3x - 4 = 14 \\ 9x = 14 + 4 \\ 9x = 18 \\ x = \frac{18}{9} \\ x = 2$

4)

$(7x - 14)(x + 8) = 0 \\ \\ \\ 7x - 14 = 0 \\ 7x = 14 \\ x = \frac{14}{7} \\ x = 2 \\ \\ \\ x + 8 = 0 \\ x = - 8$

Ответ: х = -8, х = 2 (два корня).

5)

$6x - 22 = 8(x - 12) \\ 6x - 22 = 8x - 96 \\ 6x - 8x = - 96 + 22 \\ - 2x = - 74 \\ x = \frac{ - 74}{ - 2} \\ x = 37$

II в.

1)

$8 - 0.8x = 0 \\ - 0.8x = - 8 \\ x = \frac{ - 8}{ - 0.8} \\ x = 10$

2)

$7x - 4 = x - 16 \\ 7x - x = - 16 + 4 \\ 6x = - 12 \\ x = \frac{ - 12}{6} \\ x = - 2$

3)

$3y - (5 - y) = 11 \\ 3y - 5 + y = 11 \\ 4y = 11 + 5 \\ 4y = 16 \\ y = \frac{16}{4} \\ y = 4$

4)

$(3x + 9)(x - 6) = 0 \\ \\ \\ 3x + 9 = 0 \\ 3x = - 9 \\ x = \frac{ - 9}{3} \\ x = - 3 \\ \\ \\ x - 6 = 0 \\ x = 6$

Ответ : х = -3, х = 6.

5)

$10x + 15(5 - x) = 65 \\ 10x + 75 - 15x = 65 \\ - 5x = 65 - 75 \\ - 5x = - 10 \\ x = \frac{ - 10}{ - 5} \\ x = 2$