Question

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1. 4 ( x -2 ) = 7 x + 9
2. 2 ( 2x + 4 ) = 5 ( x + 1
3. X supra 2 + 5 = 2x + 7 supra 4

Answer 1

1)

4 ( x -2 ) = 7 x + 9

4x - 8 = 7x + 9

4x - 7x = 9 + 8

-3x = 17

$\bf x=-\dfrac{17}{3}$

2)

2 ( 2x + 4 ) = 5 ( x + 1)

4x + 8 = 5x + 5

8 - 5 = 5x - 4x

3 = x

x = 3

3)

$\bf \dfrac{x}{2}+5=2x+\dfrac{7}{4}\:\:|\cdot4$

$\bf 2x+20=8x+7$

$\bf 20-7=8x -2x$

$\bf 6x =13$

$\bf x = \dfrac{13}{6}$

Answer 2

Răspuns:

1. $-\frac{17}{3}$

2. 3

3. $-\frac{49}{10}$

Explicație pas cu pas:

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1. 4 (x-2) = 7x + 9

4x - 8 = 7x + 9

4x - 7x = 9 + 8

-3x = 17

$x = -\frac{17}{3}$

2.  2 ( 2x + 4 ) = 5 ( x + 1 )

4x + 8 = 5x + 5

4x - 5x = 5 - 8

-x = -3

x = 3

3. $\frac{x}{2+5} = \frac{2x + 7}{4}$

$\frac{x}{7} = \frac{2x+7}{4}$

4x = 7 (2x + 7)

4x = 14x + 49

4x - 14x = 49

-10x = 49

$x = -\frac{49}{10}$