Question

calculo e resposta
y=-x²+2x+15

Answer 1

y = - x² + 2x + 15
0 = - x² + 2x + 15
- x² + 2x + 15 = 0
a = - 1; b = 2; c = 15

Δ = b² - 4ac
Δ = 2² - 4.(-1).15
Δ = 4 + 4.15
Δ = 4 + 60
Δ = 64

x = - b +/- √Δ = - 2 +/- √64
           2a           2.( - 1)

x = - 2 + 8  = 6/ - 2 = - 3
        - 2

x = - 2 - 8  = - 10/ - 2 = 5
        - 2

R.: x = - 3 e x = 5