Question

VA ROG E URGENT DAU COROANA ​

Answer 1

Răspuns:

5.

abc + bca + cab

= a·10²+b·10+c+ b·10²+c·10+a+ c·10²+a·10+b =

= a(10²+10+1)+b(10²+10+1)+c(10²+10+1) =

= (10²+10+1)(a+b+c) =

= 111·(a+b+c) =

= 37·3·(a+b+c) - divizibil cu 37

6.

x- numar truse continand cate 4 creioane

y - numar truse continand cate 2 stilouri

⇒ numar total creioane = 4·x

numar total stilouri = 2·y

32 - numar total creioane+ stilouri

⇒ 32=4·x+2·y

10 numar total truse ⇒ x+y=10

⇒$\left \{ {{4x+2y=32} \atop {x+y=10}} \right.$

x+y=10 ⇒ y=10-x

4·x+2·y=32 ⇔4·x+2·(10-x)=32 ⇔ 4x+20-2x=32 ⇔ 2x = 12 ⇒ x=6

y=10-x=10-6=4

⇒ 6 truse creioane

4 truse stilouri