(3x+1):5-(2x-1):3=(7x+3):15
C решением

(3х+1):5 - (2х-1):3 = (7х+3):15
[tex] \frac{3x}{5} + \frac{1}{5} - \frac{2x}{3} - \frac{1}{3}= \frac{7x}{15}+ \frac{3}{15} [/tex]
[tex] \frac{3x}{5} - \frac{2x}{3} - \frac{7x}{15} =- \frac{1}{5} + \frac{1}{3} + \frac{3}{15} [/tex]
[tex] \frac{9x-10x-7x}{15}= \frac{-3+5+3}{15} [/tex]
[tex] -\frac{8x}{15}= \frac{5}{15} [/tex]
-8x = [tex] \frac{5}{15} [/tex] * 15
-x = [tex] \frac{5}{8} [/tex]
x = [tex]- \frac{5}{8} [/tex]

[tex] \frac{3x+1}{5} - \frac{2x-1}{3}= \frac{7x+3}{15} /*15 \\ \\ \frac{15*(3x+1)}{5} - \frac{15*(2x-1)}{3}= \frac{15*(7x+3)}{15} \\ \\ 3*(3x+1)-5*(2x-1)=7x+3\\9x+3-10x+5=7x+3\\-x-7x=3-3-5\\-8x=-5\\x=0.625[/tex]