1.8 a) y=
x-1 ≥ 0
x≥1
(3,8+7,15)*0,11= 10.95 * 0.11 = 1.2045
13,2:1,2-4,7= 11 - 4.7 = 6.3
x+4+x+3=10
(-x+4)+x-3=10
x+4-(x-3)=10
-(x+4)-(x+3)=10
x1=4,5; x2=5,5