Question

Calculati: $\frac{2x}{15} + \frac{3x}{5} + 1,(6)x - 0,4x - x$

Answer 1

$\frac{2x}{15}+ \frac{3x}{5}+1,(6)x-0,4x-x= \\ =x( \frac{2}{15}+ \frac{3}{5}+1,(6)-0,4-1)= \\ =x( \frac{2}{15} + \frac{9}{15} + \frac{16-1}{9}- \frac{4}{10}-1)= \\ =x( \frac{11}{15}+ \frac{15}{9}- \frac{2}{5}-1)= \\ =x( \frac{11}{15}+ \frac{5}{3} - \frac{6}{15}- \frac{15}{15})= \\ =x( \frac{11}{15}+ \frac{25}{15} - \frac{6}{15}- \frac{15}{15} )= \\ =x* \frac{11+25-6-15}{15} = \\ =x* \frac{15}{15}= \\ =x.$

Answer 2

1,(6)=(16-1)/9=15/9=simplif.cu 3=5/3
0,4=4/10=simplif.cu 2=2/5
2x/5+3x/5+5x/3-2x/5-x/1=aducem la acelasi numitor care este 15=
2x/15+(3x·3)15+(5x·5)15-(2x·3)/15-15x/15=dam factor comun pe x/15
x/15(2+9+25-6-15)=15x/15=x