Question

Помогите решить уравнение
(5y-7)*(4y-0,8)=0
(3,7x-1,24)*2,5=8
(5,4y+8,3)*2,1=23,1
(4,2y-3,96)*1,5=8,55

Answer 1

1)
$(5y - 7)(4y - 0.8) = 0$
$5y - 7 = 0 \ 5y = 7 \ y = frac{7}{5} = 1 frac{2}{5}$
или
$4y - 0.8 = 0 \ 4y = 0.8 \ y = frac{0.8}{4} = 0.2$
Ответ: 0,2; 1 2/5.

2)
$(3.7x - 1.24) times 2.5 = 8 \ 3.7x - 1.24 = frac{8}{2.5} \ 3.7x - 1.24 = 3.2 \ 3.7x = 1.24 + 3.2 \ 3.7x = 4.44 \ x = frac{4.44}{3.7} = frac{444}{100} div frac{37}{10} = frac{444}{100} times frac{10}{37} = frac{12}{10} = 1.2$
Ответ: 1,2.

3)
$(5.4y + 8.3) times 2.1 = 23.1 \ 5.4y + 8.3 = frac{23.1}{2.1} = frac{231}{10} div frac{21}{10} = frac{231}{10} times frac{10}{21} = 11 \ 5.4 y+ 8.3 = 11 \ 5.4 y= 11 - 8.3 = 2.7\ y = frac{2.7}{5.4} = frac{1}{2} = 0.5$
Ответ: 0,5.

4)
$(4.2y - 3.96) times 1.5 = 8.55 \ 4.2y - 3.96 = frac{8.55}{1.5} = frac{855}{100} div frac{15}{10} = frac{855}{100} times frac{10}{15} frac{57}{10} = 5.7 \ 4.2y - 3.96 = 5.7 \ 4.2y = 5.7 + 3.96 = 9.66 \ y = frac{9.66}{4.2} = frac{966}{100} times frac{10}{42} = frac{23}{10} = 2.3$
Ответ: 2.3