Question

tìm x biết : (x+2)^2 - (x-3)(x+3) = -3

Answer 1

=>x^2+4x+4-x^2+9=-3

=>4x+13=-3

=>4x=-16

=>x=-4

Answer 2

\(\left(x+2\right)^2-\left(x-3\right)\left(x+3\right)=-3\\ \Leftrightarrow x^2+4x+4-x^2-9=-3\\ \Leftrightarrow x^2-x^2+4x=-3-4+9\\ \Leftrightarrow4x=-16\\ \Leftrightarrow x=-4\)

Vậy \(S=\left\{-4\right\}\)