Question

como resolver x2-x-20=0

Answer 1

x²-x-20=0

∆= b²- 4ac
∆= (-1)² - 4.1.(-20)
∆= 1+80
∆= 81

-b±√∆/2a
-(-1)±√81/2.1
1±9/2

x¹ = 10/2 = 5
x² = -8/2 = -4