Question

Daca a+b=20 si b+c=33 cat face 3a+7b+4c plz repede

Answer 1

a + b = 20    si   b + c = 33

3 a + 7 b + 4 c = 192

= 3 a + 3 b + 4 b + 4 c =

= 3 × ( a + b ) + 4 × ( b + c ) =

= 3 × 20 + 4 × 33 =

= 60 + 132 =

= 192