Question

f(x)=x²+2x-5 f(x)=3 x=?

​

Answer 1

Ответ:  x= -4  или  х=2 .

$f(x)=x^2+2x-5\ \ ,\ \ \ f(x)=3\\\\x^2+2x-5=3\ \ \ \Rightarrow \ \ \ x^2+2x-8=0\ \ ,\ \ D=36\ ,\\\\x_1=-4\ ,\ x_2=2$