Question

am nevioe urgent de raspunsuri...dau coroana tuturor celor care imi raspund!!!

Answer 1

1. 0,(6)=6/9=2/3 inversul este 3/2
2. 5/6=(x-1)/12, x-1=10, x=11
3. ma=(7/4+1/6)/2=(21/12+2/12)/2=23/12:2=23/24
 23/24-1/6=23/24-4/24=19/24
4.0,25·420=1/4·420=105
5.x-7/12=1/3  |·12
12x-7=4
12x=11
x=11/12
6.(7/4-11/4):6/9·3/9=
-4/4:2/3·1/3=-1·3/2·1/3=-1/2
7.x- suma elevului
x-4/15·x-32=23
11/15·x=23+32
11/15·x=55  |:11
x/15=5
x=5·15
x=75
A avut 75lei.
8. (2x-3)/(x+1)=1⇒2x-3=x+1⇒x=4
A={4}
15/(y+3)∈N⇒(y+3)∈{1; 3; 15} si y∈N⇒ y∈{0, 12}
B={0; 12}
A∪B={0; 4; 12}
A∩B=Ф