Question

x^2-15x=0
x^2+=0
x^2+5x+6=0

Answer 1

X^2-15x=0
х*(х-15) = 0
х = 0
х-15 = 0
х = 15
x^2+1=0
x^2 = -1
корней нет.
x^2+5x+6=0
D = 25+24 = 49
√D = 7
x1 = (-5+7)2 = 1
[2 = (-5-7)2 = -6

Answer 2

тоесть x^2+1=0