Раскройте скобки: 5-(-х-7,2)=8,6 ; (2х-5)-(3х-7)=4

Question

Раскройте скобки:
5-(-х-7,2)=8,6 ;
(2х-5)-(3х-7)=4

Answer 1

1.
5-(-х-7.2)=8.6
5+х+7.2=8.6
12.2+х=8.6
х=8.6-12.2
х=-3.6
5-(3.6-7.2)=8.6
5-(-3.6)=8.6
8.6=8.6

2.
(2х-5)-(3х-7)=4
2х-5-3х+7=4
-х+2=4
-х=4-2
-х=2
х=-2
(2*(-2)-5)-(3*(-2)-7)=4
4=4