Question

Rezolvaţi ecuaţiile
a)
$2x - 7 = 4x + 3$
b)
$4x - 5 \times (x - 1) = - 2x + 4$
c)
$\frac{3x}{4} - \frac{1 - 2x}{3} = x - \frac{7}{6}$

Answer 1

$a) \\ \\ 2x - x \times 4 = 3 + 7 \\ \\ - 2x = 10 \\ \\ x = - 5 \\ \\ b) \\ \\ - x + 5 = - 2 \times x + 4 \\ \\ - x + x \times 2 = 4 - 5 \\ \\ x = - 1 \\ \\ c) \\ \\ \frac{17x - 4}{12} = x - \frac{7}{6} = 17x - 4 = 12(x - \frac{7}{6}) \\ \\ 17x - 4 = 12 \times \frac{6x - 7}{6} = 17x - 4 = \frac{(6x - 7) \times 12}{6} \\ \\ 17x - 4 = (6x - 7) \times 2 = 17x - 4 = 12x - 14 \\ \\ 17x - x \times 12 = - 14 + 4 \\ \\ 5x = - 10 \\ \\ x = - 2$

Answer 2

a)

2 x - 7 = 4 x + 3

4 x + 3 = 2 x - 7

4 x - 2 x = - 7 - 3

2 x = - 10

x = ( - 10 ) : 2

x = - 5

b)

4 x - 5 x + 5 = - 2 x + 4

- x + 2 x = 4 - 5

x = - 1

c)

3 x / 4 - ( 1 - 2 x ) / 3 = 6 x / 6 - 7 / 6

cmmmc al numitorilor ( 4; 3; 6 ) = 12

9 x - 4 ( 1 - 2 x ) - 12 x = - 14

9 x - 4 + 8 x - 12 x = - 14

17 x - 12 x = - 14 + 4

5 x = - 10

x = ( - 10 ) : 5

x = - 2