Question

решите уравнения :

1) 2x + 1
———— = 1
5

2) 3x + 7. 6x+4
———— = ————
5. 5

3) 3x-8
——— = -1
2

4) 7x-3. 5x + 1
——— = ————
6. 2

5) 11-3x
———— = 1/2
4
​

Answer 1

$1) \: \: \frac{2x + 1}{5} = 1 \\ 2x + 1 = 5 \\ 2x = 5 - 1 \\ 2x = 4 \\ x = 4 \div 2 \\ x = 2$

$2) \: \: \frac{3x + 7}{5} = \frac{6x + 4}{5} \: \: | \div 5 \\ 3x + 7 = 6x + 4 \\ 3x - 6x = 4 - 7 \\ - 3 x= - 3 \\ x = - 3 \div ( - 3) \\ x = 1$

$3) \: \: \frac{3x - 8}{2} = - 1 \\ 3x - 8 = - 1 \times 2 \\ 3x - 8 = - 2 \\ 3x = - 2 + 8 \\ 3x = 6 \\ x = 6 \div 3 \\ x = 2$

$4) \: \: \frac{7x - 3}{6} = \frac{5x + 1}{2} \\ 3(7x - 3) = 6(5x + 1) \\ 21x - 9 = 30x + 6 \\ 21 x - 30x = 6 + 9 \\ - 9x = 15 \\ x = - \frac{15}{9} \\ x = - \frac{5}{3} \\ x = - 1 \frac{2}{3}$

$5) \: \: \frac{11 - 3x}{4} = \frac{1}{2} \\ 2(11 - 3x) = 4 \: \: | \div 2 \\ 11 - 3x = 2 \\ 3x = 11 - 2 \\ 3x = 9 \\ x = 9 \div 3 \\ x = 3$