0.55 (x+4) = 5.5(2x-3)
0.55x + 0.55*4 = 5.5*2x - 5.5*3
0.55x + 2.2 = 11x - 16.5
0.55x -11x = -16.5-2.2
-10.45x = -18.7
x= -18.7 : (-10,45)= 1870/1045 = 374/209 =34/19
х=1 15/19
3(а-1)^2+6a=3(a^2-2a+1)+6a=3a^2-6a+3+6a=3a^2+3
126ц20кг+14ц89кг=140ц109кг==141ц9кг
(3-3)*3+3/3=1
(3+3)*3-3*3=9
(3-3)3+3+3= 6
и т.д