Question

resolva as equaçoes:a) x(x+4)+x(x+2)=2x+12

Answer 1

x (x + 4 ) + x (x + 2 ) = 2x + 12
x² + 4x + x² + 2x = 2x + 12
2x² + 6x = 2x + 12
2x² + 6x - 2x - 12 = 0
2x² + 4x - 12 = 0
a = 2
b = 4 
c = - 12
Δ = b² - 4.a.c
Δ = 4² - 4. 2 . (-12)
Δ = 16 + 96
Δ = 112
x =  -b + - √Δ/2a
x = - 4 + - √112 / 2.2
x = - 4 + - √112/4
x' = - 1 + 4 √7
x" = - 1 - 4 √7

S = { - 1 + 4 √7  e - 1 - 4 √7 }