(1 : 6/11 - 2 3/4 * 0,5) * 4 4/11=(1*11/6 - 11/4 * 0,5) * 48/11=
=(11/6 - 11/8) * 48/11=(44/24 - 33/24) * 48/11=11/24*48/11=48/24=2
x^2+2x-3=0
D = b² - 4ac = 22 - 4·1·(-3) = 4 + 12 = 16
x1 = (-2 - √16)/(2·1) = (-2 - 4)/2 = -6/2 = -3
x2 = (-2 + √16)/(2·1) = (-2 + 4)/2 = 2/2 = 1