Răspuns:
Explicație pas cu pas:
1) a = ((4/10 -6/90)^2):12/9 =
(2/5 -1/15)^2:4/3 =
((6-1)/15)^2:4/3 =
(1/3)^2:4/3 =
1/9*3/4 = 3/36 = 1/12
Inversul = 12
2) 3c +2s = 24
5c +2s = 31 |*-1
3c +2s = 24
-5c -2s = -31 le adunam:
-2c +0 = -7
c = -7/-2 = 7/2
3*7/2 +2s = 24
21 +4s = 48
4s = 27
s = 27/4 = 6,75 lei sticla
