Są dwie kartki zadań prosiłabym o pomoc , bo to hehe na zaliczenie klasówki.

Zad.11 s = 495m = 0,495 km t = 1,5s = 0,025h s = 3,3 km x - poszukiwany czas 0,025h = 0,495 km x = 3,3 km x = (3,3 * 0,025) : 0,495 x = 0,0825 : 0,495 x = 0,1(6) h x w przybilżeniu = 0,17 h x = 10,2 s Zad.20 a) 2(x -y) + 3(x - 5) = 4 3(x + 2) - (y -3) = 5 2x - 2y + 3x - 15 = 4 3x + 6 - y + 3 = 5 5x - 2y = 19 - y = -3x -4/: (-1) 5x - 2(3x + 4) = 19 y = 3x + 4 5x - 6x - 8 = 19 y = 3x + 4 -x = 11/: (-1) y = 3x + 4 x = -11 y = -29 b) y + 2x = 11 2x - 6y = 4 y = 11 - 2x 2x -6(11 - 2x) = 4 y = 11 - 2x 2x - 66 + 12x = 4 y = 11 - 2x 14x = 70/: 14 y = 11 - 2x x = 5 y = 1 x= 5 c) x - y + 2 = 0 2 i 1/2 y - 1 i 1/2 x = 2 x = y - 2 5/2y - 3/2x = 2 x = y - 2 5/2y - 3/2( y - 2) = 2 x = y - 2 y= - 1 x = -3 y = -1 d) y + 9/3 + 2 - x/4 = 1 - 2x 2y - 3x/4 = 2/3y + 1 4y + 36/12 + 6 - 3x/12 = 1-2x 6y - 9x/12 - 8/12y = 1 (4y + 42 - 3x)/12 = 1-2x (16/3y - 9x)/12 = 1 1/3y + 3,5 - 1/4x = 1 - 2x 2/3y - 0,75x = 1 1/3y + 7/4x = -2,5 2/3y - 0,75x = 1 1/3y = -2,5 - 7/4x /: 1/3 2/3y - 0,75x = 1 y = -7,5 - 5,25x 2/3( -7,5 - 5,25x) - 0,75x = 1 y = -7,5 - 5,25x - 4,25x = 6/: (-4,25) y = -7,5 - 5,25x x = -1,41 y = -14,90 x = -1,41 e) 2(x -3) - y = 4 3(y + 2) + 2x = 0 2x - 6 - y = 4 3y + 6 + 2x = 0 -y = 10 - 2x/: (-1) 3y + 6 + 2x = 0 y = -10 + 2x -30 - 6x + 2x = 0 y = -10 + 2x -4x = 30/: (-4) y = -10 + 2x x = -7,5 y = -25 x = - 7,5 f) x/2 + y = 4 x - y/3 = 1 1/2x + y = 4 x - 1/3y = 1 1/2x + y = 4 x = 1 + 1/3y 1/2 + 7/6y = 4 x = 1 + 1/3y 7/6y = 4 - 1/2 x = 1 + 1/3y 7/6y = 7/2/ : 7/6 x = 1 + 1/3y y = 3 x = 2 Ad.1 3x - 8 + x = 2(2x - 4) 4x - 8 = 4x - 8 Odp. C Ad.3 Odp.A Ad.4 Odp.C Ad.8 -3x + 4y = 14 2x - 3y = -10 -3x + 4y = 14 2x = 3y - 10/: 2 -3x + 4y = 14 x = 3/2y - 5 - 4,5 + 15 -14 = -4y x = 3/2y - 5 -4y = -3,5/: (-4) x = 3/2y - 5 y = 0,875 x = -3,6875