Question

Quanto é (x+6)ao quadrado=121????

Answer 1

(x+6)² = 121
(x+6) . (x+6) = 121
x² + 6x + 6x + 36 = 121
x² + 12x + 36  - 121 = 0
x² + 12x - 85 = 0

a = 1
b = 12
c = -85

Δ = b² -4 .a . c
Δ = 12² - 4 . 1 . (-85)
Δ = 144 + 340
Δ = 484

$\mathtt{\dfrac{-b+-~\sqrt{\Delta}}{2~.~a}~~=~~\dfrac{-12 +-~\sqrt{484}}{2~.~1}~~=~~\dfrac{-12+-~22}{2}} \\ \\ \\ \mathtt{x' =\dfrac{-12+22}{2}~~=~~\dfrac{10}{2}~~=~~5} \\ \\ \\ \mathtt{x''= \dfrac{-12-22}{2}~~=~~-\dfrac{34}{2}~~=~~-17} \\ \\ \\ \boxed{\boxed{\mathtt{Resposta: S:-17~~~e~~~5}}}$