Question

numărul rațional x din proporția 1,(6)/1,25-0,2(7)=4/x este egal cu: A. 2/3 B. 4/5 C. 6/7 D. 7/3​

Answer 1

Răspuns:

$\frac{\frac{16-1}{9}}{1,25} -\frac{27-2}{90} =\frac{4}{x} \\\\\frac{15}{9} *\frac{100}{125} -\frac{25}{90} =\frac{4}{x} \\\\\frac{1500}{1125} -\frac{25}{90} =\frac{4}{x} \\\\\frac{4}{3} -\frac{5}{18} =\frac{4}{x} \\\\\frac{24}{18} -\frac{5}{18} =\frac{4}{x} \\\\\frac{19}{18} =\frac{4}{x} = > 19x=4*18= > x=\frac{72}{19}$