Question

30 БАЛЛОВ решите не из интернета
3 пример

Answer 1

Вроде верно..................................,,,................

Answer 2

$\displaystyle \tt \frac{4}{7}\cdot(0,56-4,2y)+0,4=\frac{5}{13}\cdot(0,52-6,5y)\\\\\frac{4\cdot56}{7\cdot100}-\frac{4\cdot42y}{7\cdot10}+0,4=\frac{5\cdot52}{13\cdot100}-\frac{5\cdot65y}{13\cdot10}\\\\0,32-2,4y+0,4=0,2-2,5y\\\\0,1y=0,2-0,72\\\\y=-5,2\\\\----------\\\\\ \frac{4}{7}\cdot(0,56+4,2\cdot5,2)+0,4=\frac{5}{13}\cdot(0,52+6,5\cdot5,2)\\\\\frac{4}{7}\cdot22,4+0,4=\frac{5}{13}\cdot34,32\\\\13,2=13,2$