Question

(x-3)(x+7)=-9 решите уравнение

Answer 1

X^2-3x+7x-21=-9
X^2+4x-12=0
D=16-4×1×(-12)=64
X1=-4-8÷2=-6
X2=-4+8÷2=2

Answer 2

х^2+7х-3х-21+9=0
х^2+4х-12=0
D=b^2-4ac=16-4•(-12)=16+48=64>0
x1=(-b+√D)/2a=(-4+√64)/2=(-4+8)/2=
4/2=2
x2=(-4-8)/2=-6
ответ 2;-6