Question

9.Se stie ca:ab+ac=420 si b+c=14 Aflati A.
10.Se stie ca:ab-ac=135 si a = 9 Aflati b-c​

Answer 1

Răspuns:

ab+ac=420

b+c=14

ab+ac=a(b+c)=420=>14a=420=>a=420:14=>a=30

____________

ab-ac=135

a = 9

ab-ac=a(b-c)=135=>9(b-c)=135=>b-c=135:9=>b-c=15

Answer 2

9)

ab+ac=420

a×(b+c)= 420

a×14=420|÷14

a=420÷14

a=30

10)

ab-ac=135

a×(b-c)=135

9×(b-c)=135|÷9

b-c=135÷9

b-c=15