Question

Помогите пожалуйста решить уравнения.
0.3( 6-3у)=4.5-0.8(у-9) ; 5/6(1/2х-2/3)=3х-2 1/4; 4/9х+14=1/6х+9.

Answer 1

Ответ:

$1) 0,3(6 - 3y) = 4,5 - 0,8(y - 9)\\\\1,8 - 0,9y = 4,5 - 0,8y + 7,2\\\\-0,9y + 0,8y = 4,5 + 7,2 - 1,8\\\\-0,1y = 9,9\\\\ y = -99$

$2) \frac{5}{6}(\frac{1}{2}x - \frac{2}{3}) = 3x - 2\frac{1}{4}\\\\\frac{5\cdot1}{6\cdot2}x - \frac{5\cdot2}{6\cdot3} = 3x - 2\frac{1}{4}\\\\\frac{5}{12}x - \frac59 = 3x - \frac{9}{4}\\\\\frac{5}{12}x - 3x = -\frac94 + \frac59\\\\-2\frac{7}{12}x = \frac{-81+20}{36}\\\\-\frac{31}{12}x = -\frac{61}{36}\\\\x = \frac{61\cdot12}{36\cdot31} = \frac{61}{93}$

$3) \frac49x+14=\frac16x+9\\\\\frac49x-\frac16x = 9 - 14\\\\\frac{16-6}{36} x = -5\\\\\frac{10}{36}x = -5\\\\x = -\frac{5\cdot36}{10} = -\frac{36}{2} = -18$