Question

Fie a, b apartin R. determinati a, b stiind ca a+b= 13 si a*b=18

Answer 1

Răspuns:

Explicație pas cu pas:

a,b ∈ R

a+b= 13

a·b=18

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a = 13-b =>

(13-b)·b = 18 =>

13b-b²=18  =>

b²-13b+18 = 0  =>

b₁,₂ = [13±√(169-4·18)]/2

b₁,₂ = (13±√97]/2

b₁ = (13-√97)/2

a₁ = 13-13+√97/2  => a₁ = √97/2

b₂ = (13+√97)/2

a₂ = 13-13-√97/2 => a₂ = -√97/2

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