Question

Daca a+b=33 si a+c=11 ,calculati : 5.a+3.b+2.c

Answer 1

5.a+3.b+2.c=3a+2a+3b+2c

scoatem in factori:

3(a+b)+2(a+c)

inlocuim a+b=33 si a+c=11

3·33+2·11=99+22=121

Answer 2

a + b = 33;  a + c = 11

5a + 3b + 2c =?

[a + b = 33] ×3     ⇒  3a + 3b = 99

[ a + c = 11] ×2      ⇒   2a + 2c = 22

deci 5a + 3b + 2c = 99 + 22

5a + 3b + 2c = 121