Question

eu quero (x+3).(x-5)

Answer 1

( x + 3) * (x - 5) = 
x² - 5x + 3x - 15 = 0
x² -2x - 15 = 0

Δ = b² - 4ac
Δ = -2² - 4 * 1 * -15
Δ = 4 + 60
Δ = 64

x = -b +- √Δ / 2 * a
x = - (-2) +- √64/2

x' = 2 + 8 / 2 ---->10/2 ---->5
x" = 2 - 8 / 2-----> -6 / 2 ---> -3

S = { -3, 6 }

Answer 2

Eu quero (x+3).(x-5)
x² - 5x + 3x -15 
x² - 2x - 15 
assim
(x + 3)( x - 5) = x² - 2x - 15