Răspuns:
x(y+z) = xy+xz=16+18
x(y-z)=36; xy-xz=36; 2(xy-xz) = 2*36
x(y+z)=42; y+z=7; x/7=42; x=7*42
3x(y-z)= 48; x=2; 3*2(y-z)=48; y-z=48/3=16
x+y=9; y+z=10; 3x+2y+5z= ?
y=9-x ; z=10-y=10-9+x=1+x
x+1+x=9; 2x=8; x=4; y=5; z=5
3x+2y+5z= 3*4+2*5+5*5
Explicație pas cu pas:
