Odpowiedź:
1. [tex]\frac{x}{3} - 2 = 2x - \frac{x+3}{6}[/tex] / *6
2x-12=12x-(x+3)
2x-12=12x-x-3
2x-12=11x-3
2x-11x=12-3
-9x=9
-x=1
x=-1
2. [tex]\frac{2}{5}[/tex] x - 0,4 = 2 (0,75 - [tex]\frac{1}{5}[/tex]x) + 0,1
[tex]\frac{2}{5} x - \frac{2}{5} =2(\frac{3}{4} - \frac{1}{5} x)+ \frac{1}{10}[/tex]
[tex]\frac{2}{5}x-\frac{2}{5}=\frac{3}{2} - \frac{2}{5}x + \frac{1}{10}[/tex]
[tex]\frac{2}{5}x-\frac{2}{5}= \frac{8}{5} - \frac{2}{5}x[/tex]
2x-2=8-2x
2x+2x=8+2
4x=10
x=2[tex]\frac{1}{2}[/tex]
3. [tex]\frac{1}{3}[/tex]( [tex]x^{2}[/tex]+ x) +[tex]\frac{2}{3}[/tex] = 2 ( [tex]\frac{2}{3}[/tex] - 2x) + 11 + [tex]\frac{1}{3}x^{2}[/tex]
[tex]\frac{1}{3} x^{2}+\frac{1}{3} x + \frac{2}{3}= \frac{4}{3} -4x+11+\frac{1}{3} x^{2}[/tex]
[tex]\frac{1}{3} x + \frac{2}{3}= \frac{4}{3} - 4x+11[/tex]
[tex]\frac{1}{3} x + \frac{2}{3} = \frac{37}{3}-4x\\[/tex]
x+2=37-12x
12x+x=37-2
13x=35
x=2[tex]\frac{9}{13}[/tex]