Question

Determine a raiz da função quadratica de x2-2x-15

Answer 1

x²  - 2x- 15 = 0

Δ= b² - 4.ac

Δ= (-2)² - 4.1.(-15)

Δ= 4 + 60

Δ= 64

x = – b ± √Δ/2∙a

x = -(-2) ± √64/2∙1

x = 2 ± 8/2

x' = 2+8/2  

x'  =10/2

x' =  5  

x'' = 2 – 8/2

x'' = -6/2

x'' = -3