Question

Daca x+y=2,5 si y+z=6,4, calculati:
a)3x+6y+3z
b)5x+7y+2z

Answer 1

a) 3x+6y+3z=(3x+3y)+(3y+3z)=
=3(x+y)+3(y+z)=3*2,5+3*6,4= 26,7

b) 5x+7y+2z=5x+5y+2y+2z=
=5(x+y)+2(y+z)=5*2,5+2*6,4=12,5+12,8=25,3

Answer 2

a. 3x+6y+3z= 3( x+2y+z)=3(x+y+y+z)=3*8,9=26,7
b.5x+7y+2z=5x+5y+2y+2z=5(x+y)+2(y+z)=5*2,5+2*6,4=25,3