Question

в) (х-5):0,7 = (2х-9):0,4;
г) х:(3,8-х) = х:(5,6-3х).

P.S. Заранее спасибо!

Answer 1

в)
$frac{x-5}{0,7}= frac{2x-9}{0.4} \ (x-5)0.4=(2x-9)0.7 \ 0.4x-2=1.4x-6.3 \ 0.4x-1.4x=2-6.3 \ -x=-4.3 \ x=4.3$

г)
$frac{x}{3.8-x}= frac{x}{5.6-3x} \ 3.8-x neq 0; 5.6-3x neq 0 \ x(5.6-3x)=x(3.8-x) \ 5.6x- 3 x^{2} =3.8x- x^{2} \ -3 x^{2} + x^{2} -3.8x+5.6x=0 \ -2 x^{2} +1.8x=0 \ 2 x^{2} -1.8x=0 \ x(2x-1.8)=0 \ x_{1}=0 \ x_{2} =0.9$