Question

Alguém sabe resolver essa equação de 2 grau ?

x(2x + 1 )/3 = 5

Answer 1

x (2x + 1) /3 = 5

2x² + x/3 = 5
2x² + x = 3.5
2x² + x - 15 = 0

Agora faz por Bháskara

a = 2  b= 1  c= -15

Δ= b² -4ac
Δ = 1 - 4.2.(-15)
Δ = 1 + 120
Δ = 121

x = -b +/- √Δ
         2a

x = -1 +/- 11
         4

x' = -1 + 11/4
10/4 = 5/2

x" = -1 -11/4
-12/4 = -3

Espero ter ajudado (:

Answer 2

$\frac{x(2x+1)}{3} =5\\ \\2x^2+x=15\\2x^2+x-15=0\\ \\\Delta=1^2-4.2.(-15)\\\Delta=121$

$x=\frac{-b\pm\sqrt\Delta}{2a}$

$x= \frac{-1\pm11}{4}$

$\boxed{x_1=\frac{5}{2}}$

$\boxed{x_2=-3}$