а) <span>5d=-85,6-3d</span>
8d+85.6=0
d=-85.6/8
d=-10.7
б) (5b)/6-(5b+1)/9=(1b)/2+1//3
(5//6)b-(5*b/9+1/9)-b/2-(1//3)=0
(5//6)b-((5//9)b+(1//9))-b/2-(1//3)=0
(5//18)b-(1//9)-b/2-(1//3)=0
-(2//9)b-(1//9)-(1//3)=0
-(2//9)b-(4//9)=0
b=(4//9)/(-(2//9))
b=-2
// - черта дроби
(15-а) *50 -36=314
(15-а) *50 = 314+36
(15-а) *50 = 350
15-а= 350 :50
15-а=7
а= 15-7
а= 8
проверим:
(15-8) *50 -36 = 314
7*50 -36= 314
350-36=314
314=314
7975 = 5*5*11*29
2285 = 5*457
<span>НОД(7975, 2285) = 5</span>
63*7=441 м
847-441=406 м
406/7=58 м/мин
скорость 58 м\мин