Question

em 2x ao quadrado mais 3 x - 54 igual

Answer 1

2x² + 3x - 54 = 0 

a = 2 
b = 3
c = -54

Δ = b² - 4 .a . c
Δ = 3² -4 . 2 . (-54)
Δ = 9 - 8 . (-54)
Δ = 9 + 432
Δ = 441

$\mathtt{\dfrac{-b+-~\sqrt{\Delta}}{2~.~a}~~=~~\dfrac{-3+-~\sqrt{441}}{2~.~2}~~=~~\dfrac{-3+-21}{4}} \\ \\ \\ \mathtt{x'= \dfrac{-3+21}{4}~~=~~\dfrac{18}{4}~~(\div2)~~=~~\dfrac{9}{2}} \\ \\ \\ \mathtt{x''= \dfrac{-3 -21}{4}~~=~~-\dfrac{24}{4}~~=~~-6} \\ \\ \\ \boxed{\boxed{\mathtt{Resposta: S = -6~~~e~~~\dfrac{9}{2}}}}$