1)
a)
[tex]5x - 2 = - 7 \\ 5x = - 7 + 2 \\ 5x = - 5 \\ x = - \frac{5}{5} \\ x = - 1[/tex]
b)
[tex]4 - 2.3x = - 0.6 \\ 4 + 0.6 = 2.3x \\ 4.6 = 2.3x \\ 2.3x = 4.6 \\ x= \frac{4.6}{2.3} \\ x = 2[/tex]
c)
[tex] \sqrt{2} + 2x = \sqrt{18} \\ \sqrt{2} + 2x = \sqrt{ {3}^{2} \times 2 } \\ \sqrt{2} + 2x = 3 \sqrt{2} \\ 2x = 3\sqrt{2} - \sqrt{2} \\ \\ 2x = 2 \sqrt{2} \\ x = \frac{2 \sqrt{2} }{2} \\ x = \sqrt{2} [/tex]
2)
3(x-3)-2(1-x)=2x-2(x+4)+7
3x-9-2+2x=2x-2x-8+7
mutam termenii cu x in stânga și pe cei fără x in dreapta
3x+2x-2x+2x=-8+7+9+2
5x=10
x=10:5
x=2
6)
[tex] | \frac{3x + 1}{2} | = 10 \\ \frac{3x + 1}{2} = + 10 \: sau - 10 \\ \\ \frac{3x + 1}{2} = 10 \\ 3x + 1 = 10 \times 2 \\ 3x + 1 = 20 \\ 3 x= 20 - 1 \\ 3x = 19 \\ \boxed{x1 = \frac{19}{3} }\\ \\ \frac{3x + 1}{2} = - 10 \\ 3x + 1 = - 10 \times 2 \\ 3x + 1 = - 20 \\ 3 = - 20 - 1 \\ 3x = - 21 \\ x = - \frac{21}{3} \\ \boxed{ x2 = - 7}[/tex]
