a). 2(3x+4)-3(5x-6)+4(7x+8)=115 6x+8-15x+18+28x+32x=115 19x+58=115 19x=57:19 x=3 b). x (x-5) -x (x+4) = -63 2x-5x-2x-4x=-63 -9x=-63:-9 x=7
a) 2 (3x+4) -3 (5x-6) +4 (7x+8) = 115 6x + 8 -15x + 18 + 28x +32 = 115 19x + 58 = 115 19x = 115- 58 19x = 57 x = 57 : -19 x = 3 b) x (x-5) -x (x+4) = -63 x² -5x - x² -4x = -63 -9x = -63 x = (-63): (-9) x = 7 c) 4 (x-3) 2 = -6 chyba ze jest inny zapis ( coś z 2 po nawiasie?? (4x - 12 )*2 = -6 8x -24 = -6 8x = -6 + 24 8 x = 18 x = 18 : 8 x = 9/4 d) 30-10 (2-3x) = -50 30 - 20 +30x = -50 10 +30x = -50 30x = -50 -10 30x = -60 x = (-60) : 30 x = -2 e) 6x-7 (11+2x) +2 = - 4 (15-x) +3x 6x -77 -14x +2 = -60 +4 x + 3x -8x - 75 = -60 + 7x -8x -7x = -60 +75 -15x = 15 x = 15 : (-15) x = - 1
