Question

Ma poate ajuta cineva?Multumesc!​

Answer 1

Răspuns:

Explicație pas cu pas:

a) x²-7x+m = 0 ; x = 1

1²-7·1+m = 0 => 1-7+m = 0 => -6 = -m =>

m = 6

b) x²-mx+4 = 0 ; x = 2  =>

2²-m·2+4 = 0 => 8-2m = 0 =>

2m = 8 => m = 8:2 =>

m = 4

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2x²-2x-1 = 0

a = 2 ; b = -2 ; c = -1 ;

Δ = b²-4ac = (-2)²-4·2·(-1) = 4+8 = 12

Δ = 12 > 0 => ecuatia are solutii reale

x₁,₂ = (-b±√Δ)/2a

x₁,₂ = (2±√12)/4 = (2±2√3)/4 = (1±√3)/2

x₁ = (1-√3)/2 ; x₂ = (1+√3)/2