-1/2x+2/3x=4-3=1
1/6 x =1
x= 1*6=6
================
8 6/10 -60=86/10-60=-257/5=-51.4
8 6/10+4/19-15/38 = 86/10+4/19-15/38 =1599/190
-257/5*190/1599 =-9766/1599 ≈6.11
(674-315)+×=452
1) 674-315=359
2)452-359=83
(674-315)+83=452
А+в = (4+1; -5-7) = (5 ; -12)
║а+в║=
=√25+144=√169=13