Question

489 решите уранения​

Answer 1

Ответ: y=-27/40.

Пошаговое объяснение:

(y+(3/8))/((7/20)-(7/8))=4/7

1. y+(3/8)=(8*y+3)/8.

2. (7/20)-(7/8)=(7*2-7*5)/40=(14-35)/40=-21/40.

3. ((8*y+3)/8):(-21/40)=(8y+3)*40/(-8*21)=5*(8y+3)/(-21)=-(40y+15)/21.

4. -(40y+15)/21=4/7  |×7

-(40y+15)*7/21=4

-(40y+15)/3=4  |×(-3)

40y+15=-12

40y=-27  |÷40

y=-27/40.