rozwiąż równania kwadratowe: a)[latex]x^{2}-9x+18=0[/latex] b) [latex]-frac{1}{2}(x+5)(x-2)=0[/latex] c) [latex]x^{2}-2x+2=2x-2[/latex] d) [latex]-x^{2}+8y-15=0[/latex]   dziękuje bardzo za pomoc :)

a) x^2 - 9x +18 = 0 D = b^2 - 4ac D = 81-72 = 9 VD = V9 = 3 x1 =(-b-VD)/2a =(0-3)/2 x1 = 3 ====== x2 =(-b+VD)/2 =(9+3)/2 x2 = 6 ====== b) -1/2(x+5)(x-2) = 0 x+5 = 0 x1 = -5 ====== lub x-2 = 0 x2 = 2 ====== c) x^2 -2x+2 = 2x-2 x^2 - 4x+4 = 0 D = 16-16 = 0 x = 4/2 x = 2 ===== d) -x^2 + 8x-15 = 0 D = 64-60 = 4 VD = V4 = 2 x1 =(-8-2)/(-2) x1 = 5 ====== x2 =(-8+2)/(-2) x2 = 3 ======