Question

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Se considera numerele naturale a,b,c.
A. Daca a-b=215 si b-c=32,determinati a-c
B. Daca a-c=138 si b-c=129, calculate a-b
C. Daca a-b=72 si (a-c)-(b+c)=18,determinati numarul c.

Dau coroana daca raspundeti CORECT! Si primiti multe puncte!!!!!!

Answer 1

A .

(a - b) + (b - c) =  215 + 32

a - b + b - c = 247

a - c = 247

B.

(a - c) - (b - c) = 138 - 129

a - c - b + c = 9

a - b = 9

C.

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

a - c - b - c = 18

a - b  - 2c = 18

72 - 2c = 18

2c = 72 - 18

2c = 54

c = 54 : 2

c = 27

Answer 2

a) a-b=215 si b-c=32  a-c =?

a-b + b-c = a-c = 215+32 = 247

b) a-c=138 si b-c=129  a-b =?

(a-c) - (b-c) = a-c-b+c = a-b = 138-129 = 9

c) a-b=72 si (a-c)-(b+c)=18  c=?

(a-c)-(b+c) = a-c-b-c = (a-b) -2c <=>

18 = 72-2c => 2c = 72-18 => 2c = 54 => c = 54:2 => c = 27