Question

Ajutatima sa fac macar un variant, ca nu inteleg cum sa fac​

Answer 1

Răspuns:

Explicație pas cu pas:

{x-5y = 3 => x = 5y+3

{xy+3y = 11 =>

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{x = 5y+3

{(5y+3)·y+3y = 11 =>

5y²+6y-11 = 0 ;

a = 5 ; b = 6 ; c = -11 ; Δ = b²-4ac = 36-4·5·(-11) = 36+220 = 256 =>

√Δ = √256 = 16

y₁,₂ = (-b±√Δ)/2a = (-6±16)/10 =>

y₁ = (-22)/10 = -11/5 => x₁ = 5·(-11/5)+3 = -8

y₂ = 10/10 = 1 => x₂ = 5+3 = 8

Solutii : (x = -8 ; y = -11/5) ; (x = 8 ; y = 1)

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