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Daca x+3y=8 si y+2z=14 ,sa se calculeze:

1. 2x + 3y - 6z+26


Răspuns :

2X+3Y-6Z+26=
=2X+3Y-6z+52-26 (am adunat un 26 si l-am scazut)
=2x+3y-6z+2(28+24)-26=
=2x+3y-6z+2[(2y+4z)+(3x+9y)]-26
=2x+3y-6z+2(11y+4z+3x)-26
=2x+3y-6z+22y+8z+6x-26
=8x+25y+2z-26
=8x+24y+y+2z-26
=8 ori 8 + 14 - 26
=64+14-26
=78-26
=52