a) 2x-2y=7 2x=7+2y x=3,5+y x=4,5 4x+3y=21 4(3,5+y) +3y=21 14+7y=21 7=7y y=1
a) 2x-2y=7 /* -2 4x+3y=21 -4x + 4y = -14 4x + 3y = 21 _____________ 7y = 7 /:7 y = 1 2x-2y=7 /*3 4x+3y=21 /*2 6x - 6y = 21 8x + 6y = 42 _____________ 14x = 21 /:14 x = 1,5 b) 0,4x+0,3y=1,4 /*10 0,1x+3y=2,3 /*10 4x + 3y = 14 x + 30y = 23 /*-4 4x + 3y = 14 -4x - 120y = -92 __________________ -117y = -78 /: - 117 y = 0,(6) 0,4x+0,3y=1,4 /*10 0,1x+3y=2,3 /*10 4x + 3y = 14 /* -10 x + 30y = 23 -40x - 30y = -140 x + 30y = 23 -39x = -117 /: -39 x = 3 c) 2x+3y=14 /*3 3x-2y=8 /* -2 6x + 9y = 42 -6x + 4y = -16 ___________ 13y = 26 /:13 y = 2 2x+3y=14 /*2 3x-2y=8 /* 3 4x + 6y = 28 9x - 6y = 24 _____________ 13x = 52 /:13 x = 4
a) 2x-2y=7 4x+3y=21 2x=7+2y 4x+3y=21 4x=14+4y 4x+3y=21 4x=14+4y 14+4y+3y=21 4x=14+4y 7y=7 4x=14+4y y=1 4x=14+4 y=1 4x=18 y=1 x=4,5 y=1 b)0,4x+0,3y=1,4 0,1x+3y=2,3 4x+3y=14 x+30y=23 4x+3y=14 x=23-30y 4(23-30y)=14 x=23-30y -120y=14-92 x=23-30y y=1,5 x=23-30*1,5 y=1,5 x=-22 c)2x+3y=14 3x-2y=8 2x=14-3y 3x-2y=8 6x=42-9y 6x-4y=16 6x=42-9y 42-9y-4y=16 6x=42-9y -13y=16-42 6x=42-9y -13y=-26 6x=42-9y y=2 6x=42-18 y=2 6x=24 y=2 x=4 y=2
