Question

X2-x-20= me ajudem pfvx

Answer 1

Boa tarde!


x² -x-20 = 0

a= 1

b= -1

c= -20

∆ = b² -4.a.c

∆= (-1)²-4.1.(-20)

∆ = 1 + 80

∆ = 81

x= -b±√∆/2.a

x= -(-1)±√81/2

x' = 1+9/2

x' = 5

x" = 1-9/2

x" = -4

S= {-4,5}

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