1)
a) -2-3+8 = -5 + 8 = 3
b) 5 - 2 - 7 =3 - 7 = -4
c)(-3)(-2)-(-1) = 6 + 1 = 7
d)27:(-9)+6 = -3 + 6 = 3
2)
a) AB = AC , deci < B este la baza triunghiului = < C = 73 grade
b) AC = AB = 10cm = > P = 10 + 10 +7 = 27 cm
3)
fie unghiurile a,b,c,
a/4 = b/6= c/8 => k
a = 4k
b = 6k
c = 8k
4k +6k+8k = 180
18k = 180
k = 180 : 18
k=10
a = 40 grade
b = 60 grade
c = 80 grade