a) 2x = 7 + 2y x = (7+ 2y) : 2 4((7 + 2y) :2) + 3y = 21 14 + 4y + 3y = 21 7y = 21 - 14 y = 1 x = (7 + 2 * 1) : 2 x = 4,5
a) 2x-2y=7 4x+3y=21 2x=7+2y /:2 4x+3y=21 x=3,5+y 4(3,5+y)+3y=21 x=3,5+y 14+4y+3y=21 x=3,5+y 7y=21-14 x=3,5+y 7y=7/:7 x=3,5+y y=1 x=3,5+1 y=1 x=4,5 y=1 spr.2x-2y=7 2razy4.5-2razy1=7 9-2=7 7=7 b) 0,4x+0,3y=1,4/*10 0,1x+3y=2,3/*10 4x+3y=14 x+30y=23 4x+3y=14 x=23-30y 4(23-30y)+3y=14 x=23-30y 92-120y+3y=14 x=23-30y -117y=14-92 x=23-30y -117y= -78/:(-117) x=23-30y y= 78/117 x=23-30*78/117 y=78/117 x=23- 20 y=78/117 x=3 spr .0.1x+3y=2.3 0.1razy3+3razy78/117=2.3 0,3+234/117=2.3 0.3+2=2.3 2.3=2.3 e) 1/2x-3/4y=0 2/3x+1 i 1/4y=9 1/2x=3/4y /*2 2/3x+1 1/4y=9 x=6/4y 2/3*6/4y+1 1/4y=9 x=6/4y 1y+1 1/4y=9 x=6/4y 2 1/4y=9/*4/9 x=6/4y y=4 x=6/4*4 y=4 x=6 y=4 spr. 1/2x-3/4y=0 1/2razy6-3/4razy4=0 6/2-12/4=0 3-3=0 0=0 licze na naj
