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:

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

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

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