Odpowiedź:
[tex]a)\\\\5x+2=7-3x\\\\5x+3x=7-2\\\\8x=5\ \ /:8\\\\x=\frac{5}{8}\\\\\\b)\\\\2,1-0,3x=0,4\\\\-0,3x-0,4x=-2,1\\\\-0,7x=-2,1\ \ /:(-0,7)\\\\x=3\\\\\\c)\\\\\frac{5}{6}(x-1)=4\\\\\frac{5}{6}x-\frac{5}{6}=4\ \ /\cdot6\\\\5x-5=24\\\\5x=24+5\\\\5x=29\ \ /:5\\\\x=\frac{29}{5}\\\\x=5\frac{4}{5}[/tex]
