Question

daca a-b=72si(a-c)-(b+c)=18,determinati nr c

Answer 1

(a-c)-(b+c)=a-c-b-c=a-b-2c
a-b-2c=18
72-2c=18
2c=72-18
2c=54
c=27

Answer 2

a - b = 72

( a - c ) - ( b + c ) = 18

a - c - b - c = 18

( a - b ) - 2 × c = 18

72 - 2 × c = 18

2 × c = 72 - 18

2 × c = 54

c = 54 : 2

c = 27