Rozwiąż równanie: a) -7x^2+42x=0 b)4x^2-13x+3=0 c)x^2+10x=25 Rozwiąż nierówność: a)3x^2-2x-1_>0 b)x^2-x-6<0

Zad.1 a) ^ - do kwadratu -7x^ +42x = 0 x(-7x +42) =0 x =0, lub -7x +42 = 0 -7x = -42/:(-7) x = 6 X1 = 0, X2 =6, b) 4x^ -13x +3 = 0 D-delta D = (-13)^ -4 * 4 * 3 =169 -48 =121 VD = 121 X1 = (13-11):2*4 = 1/4 X2 = (13 +11):8 = 3 c) x^ +10x = 25 x^ +10x -25 =0 D = 10^-4(-25) = 100 +100 Vd =10V2 X1 =(-10 -10V2):2 = -5 -5V2 = -5(1+V2) X2 =(-10 +10V2):2 = -5 +5V2 = -5(1-V2) Zad.2 a) 3x^ -2x -1>0 D =(-2)^ -4 *3(-1) = 4 +12 = 16 VD =4 X1 = (2-4)/6 = -2/6 = -1/3 X2 = (2+4)/6 = 6/6 = 1 X1 > -1/3 X2 > 1 b) x^ - x -6<0 D =1 +4 = 25 VD = 5 X1 =(1-5):2 = -2 X2 =(1+5):2 = 3 X1 < -2, X2 < 3