Question

Daca a ,b,c sunt nr. naturale astfel incat a+b+c=32 si 2*a+b+2*c=57, calculati (a+c)*(3*a+2*b+3*c)

Answer 1

a+b+c=32
 2a+b+2c=57
a+b+c+a+c=57
32+a+c=57
a+c=57-32=25

(a+c)*(3a+2b+3c)  =
=(a+c)*(2a+2b+2c+a+c)  =
=(a+c)*[(2(a+b+c)+(a+c)]  =
=25*(2*32+25)=
=25*(64+25)=
=25*89=2225