Question

решите уравнение х²-15=2х через дискриминант

Answer 1

x^2 - 2x - 15 = 0 
D = 4 + 4*15 = 64 = 8^2
x1 = ( 2 + 8)/2 = 10/2 = 5;
x2 = (2 - 8)/2 = - 6/2 = - 3;

Answer 2

$x^{2} -15=2x \ x^{2} -15-2x=0 \ x^{2} -2x-15=0 \ D=b^2-4ac=64 \ sqrt{D} = sqrt{64}=8 \ x_1= frac{-b+ sqrt{D} }{2a} = frac{2+8}{2} = frac{10}{2}=5 \ x_2= frac{-b- sqrt{D} }{2a} = frac{2-8}{2}= frac{-6}{2} =-3$