Răspuns :
a+b =1500
a×2 + b×2 - 150= ?
1500×2 = 3000 (a+b)
3000-150 = 2850
a×2 + b×2 - 150= ?
1500×2 = 3000 (a+b)
3000-150 = 2850
a+b=1500
2x+2(y-150)=
=2x+2y-2*150=
=2(x+y)-300=
=2*1500-300=
=3000-300=2700
2x+2(y-150)=
=2x+2y-2*150=
=2(x+y)-300=
=2*1500-300=
=3000-300=2700