Question

1.a)3/5+x=2/3 b)x-1/3=5/3 c)2/3x=1/4 d)1,5x=6
2.calculati media aritmetica a numerelor 1/2, 1/3 si 1/4

4.determinati un numar,stiind ca daca la dublul acestuia adunam 2/5 obtinem 1,9

Answer 1

$1 \ a)\frac{3}{5}^{(3}+x^{(15}=\frac{2}{3}^{(5} \\\\ 9+15x=10 \\\\ 15x=1 \\\\ \boxed{x=\frac{1}{15}} \\\\\\ b)\frac{x-1}{3}=\frac{5}{3} \\\\ x-1=5 \\\\ \boxed{x=6} \\\\\\ c)\frac{2}{3}x=\frac{1}{4} \\\\ x= \frac{3*1}{4*2} \\\\ \boxed{x=\frac{3}{8}} \\\\\\ d)1,5x=6 \\\\ \frac{15x}{100}=6 \\\\ \frac{3x}{20}=6 \\\\ x=\frac{6*20}{3} \\\\ x=2*20 \\\\ \boxed{x=40}$

$2) ma=\frac{\frac{1}{2}^{6}+\frac{1}{3}^{(4}+\frac{1}{4}^{(3}}{3} \\\\ ma=\frac{\frac{6+4+3}{12}}{3} \\\\ ma=\frac{13}{12*3} \\\\ ma=\frac{13}{36} \\\\\\ 4)2x+\frac{2}{5}=1,9 \\\\ 2x^{(10}+\frac{2}{5}^{(2}=\frac{19}{10} \\\\ 20x+4=19 \\\\ 20x=15 \\\\ x=\frac{15}{20} \\\\ \boxed{x=\frac{3}{4}}$