Page 60 - Logika Matematika

1 + 1 + 1
2
2
2
2
2
2
2
2
2
b + c - a c + a - b a + b - c
Jawab:
a + b + c = 0 → c = –(a + b)
1 + 1 + 1
2
2
2
2
2
2
2
2
2
b + c - a c + a - b a + b - c
= 1 + 1 + 1
2
2
2
2
2
2
2
2
2
b + (a + b) - a (a +b) + a - b a + b – (a +b)
= 1 + 1 + 1
2
2
2
2
2
2
2
2
2
2
2
b + a + 2ab +b - a a + 2ab + a - b a + b – a - 2ab - b

= 1 + 1 + 1
2
2
2b + 2ab 2b + 2ab -2ab

= 1 + 1 + 1
2b (a + b) 2b (a + b) -2ab
1  1 1  1
+
−
2b (a + b)
 b a  2ab

1  a + b  1
2b (a + b) ab  2ab
−
 
1 1
= − = 0
2ab 2ab

59