Đáp án:
Giải thích các bước giải:
4x−3y5=5y−4z3=3x−5z4⇒⎧⎨⎩4x5+4z3=34y155y3−3x4=z12⇒{4x5+43(20y−9x)=34y1520y−9x=z⇒{−56x5=−122y1520y−9x=z⇒{x=61y8420y−9x=z⇒⎧⎨⎩x=61y8420y−9.61y84=z⇒{x=61y8437728y=z4x−3y5=5y−4z3=3x−5z4⇒{4x5+4z3=34y155y3−3x4=z12⇒{4x5+43(20y−9x)=34y1520y−9x=z⇒{−56x5=−122y1520y−9x=z⇒{x=61y8420y−9x=z⇒{x=61y8420y−9.61y84=z⇒{x=61y8437728y=z
Khi đó:
x−y+z=2020⇔x−0+−3x5=2020⇔25x=2020⇔x=5050⇒z=−2020x−y+z=2020⇔x−0+−3x5=2020⇔25x=2020⇔x=5050⇒z=−2020
