Question

calculati a -b-c stiind ca a+b=571 b+c=326 a+c=523

Answer 1

Pai se scad expresiile 2 cate 2 si avem a+b=571 - b+c = 326 ---------- a + b - b - c = 571 - 326 a - c = 245 apoi a + c = 523 - b + c = 326 -------------- a + c - b - c = 523 - 326 a - b = 197 apoi a + b = 571 - a + c = 523 ------------- a + b - a - c = 571 - 523 b - c = 48 cele trei expresii adunate a - c = 245 a - b = 197 b - c = 48 ------------------------- dau 2a - 2b - 2c = 245 + 197 + 48 2(a - b - c) = 490 | : 2, deci a - b - c = 245

Answer 2

a+b=571; a=571-b
b+c=326; c=326-b
a+c=523
inlocuim in a+c=523 =>571-b+326-b=523 =>897-2b= 523 =>897-523=2b =>374=2b => b= 187

a= 571-187=384
c= 326-187=139

V:a-b-c= 384-187-139= 58