Question

determinati numerele naturale a,b,c ,stiind ca:a)a+b=100,b+c=110,a+c=9. b) a+b=84, b+c=64,a+c=34

Answer 1

priama: 
a+c=9.⇒a=9-c.
b+c=110.⇒b=110-c.
9-c + 110 -c = 100.
119 -2c = 100. 
-2c = - 19. | x (-1)
c=9,5.
a= -o,5.
b=100,5.
 a doua:
b+c=64⇒b=64-c.
a+c=34⇒a=34-c.
64-c+34-c=84.
98-2c=84.
-2c=-14. | x(-1)
c=7.
a=34-7=27.
b=64-7=57.