Question

rezolvati in R inecuatia (x-3)(x+7)≥0

Answer 1

(x - 3)(x + 7) ≥ 0
x² + 7x - 3x - 21 ≥ 0
x² + 4x - 21 ≥ 0
Δ = 7² - 4 * 1 * (-21) = 49 + 84 = 133. √133.
$x_{1}$ = $\frac{-7 +√133}{2}$.
$x_{2}$ = $\frac{-7 - √133}{2}$.
S = {$\frac{-7 - √133}{2}$; $\frac{-7 +√133}{2}$}